PYRRO[1,2-b]PYRIDAZINONE COMPOUNDS

ABSTRACT

The invention is directed to pyrro[1,2-b]pyridazinone compounds and pharmaceutical compositions containing such compounds that are useful in treating infections by hepatitis C virus.

This application claims the benefit of U.S. Provisional Application No.60/815,578, filed Jun. 22, 2006.

FIELD OF THE INVENTION

The invention is directed to pyrro[1,2-b]pyridazinone compounds andpharmaceutical compositions containing such compounds that are useful intreating infections by hepatitis C virus.

BACKGROUND OF THE INVENTION

Hepatitis C is a major health problem world-wide. The World HealthOrganization estimates that 170 million people are chronic carriers ofthe hepatitis C virus (HCV), with 4 million carriers in the UnitedStates alone. In the United States, HCV infection accounts for 40% ofchronic liver disease and HCV disease is the most common cause for livertransplantation. HCV infection leads to a chronic infection and about70% of persons infected will develop chronic histological changes in theliver (chronic hepatitis) with a 10-40% risk of cirrhosis and anestimated 4% lifetime risk of hepatocellular carcinoma. The CDCestimates that each year in the United States there are 35,000 new casesof HCV infection and approximately ten thousand deaths attributed to HCVdisease.

The current standard of care is a pegylated interferon/ribavirincombination at a cost of approximately $31,000/year. These drugs havedifficult dosing problems and side-effects that preclude their use inalmost half of diagnosed patients. Pegylated interferon treatment isassociated with menacing flu-like symptoms, irritability, inability toconcentrate, suicidal ideation, and leukocytopenia. Ribavirin isassociated with hemolytic anemia and birth defects.

The overall response to this standard therapy is low; approximately onethird of patients do not respond. Of those who do respond, a largefraction relapses within six months of completing 6-12 months oftherapy. As a consequence, the long-term response rate for all patientsentering treatment is only about 50%. The relatively low response rateand the significant side-effects of current therapy anti-HCV drugtreatments, coupled with the negative long term effects of chronic HCVinfection, result in a continuing medical need for improved therapy.Antiviral pharmaceuticals to treat RNA virus diseases like HCV are few,and as described above are often associated with multiple adverseeffects.

A number of recent publications have described NS5B inhibitors useful inthe treatment of hepatitis C infection. See, e.g., U.S. PatentApplication Publication No. US 2006/0189602 (disclosing certainpyridazinones); U.S. Patent Application Publication No. US 2006/0252785(disclosing selected heterocyclics); and International Publication Nos.WO 03/059356, WO 2002/098424, and WO 01/85172 (each describing aparticular class of substituted thiadiazines).

While there are, in some cases, medicines available to reduce diseasesymptoms, there are few drugs to effectively inhibit replication of theunderlying virus. The significance and prevalence of RNA virus diseases,including but not limited to chronic infection by the hepatitis C virus,and coupled with the limited availability and effectiveness of currentantiviral pharmaceuticals, have created a compelling and continuing needfor new pharmaceuticals to treat these diseases.

SUMMARY OF THE INVENTION

The present invention describes novel pyrro[1,2-b]pyridazinone compoundsand pharmaceutically acceptable salts thereof, which are useful intreating or preventing a hepatitis C virus infection in a patient inneed thereof comprising administering to the patient a therapeuticallyor prophylactically effective amount of a pyrro[1,2-b]pyridazinonecompound.

In a general aspect, the invention relates to compounds of Formula I

whereinR¹ is independently 1-3 moieties selected from hydrogen, halo, cyano,nitro, hydroxy, —NR⁸R⁹, C₃-C₈ cycloalkyl, C₁-C₆ alkyl, alkenyl, alkynyl,C₁-C₆ haloalkyl, C₁-C₆ hydroxyalkyl, C₁-C₆ alkoxy, —(C₁-C₆alkylene)NR⁸R⁹, —C(O)OH, —C(O)O(C₁-C₆ alkyl), —C(O)NH(C₁-C₆ alkyl),—C(O)(C₁-C₆ alkyl), aryl, or heterocyclyl having 1, 2, or 3 N, O, or Satoms, wherein R⁸ and R⁹ are independently H, C₁-C₆ alkyl, C₃-C₈cycloalkyl, aryl, or heterocyclyl, or R⁸ and R⁹ combine with the N atomto which they are attached to form a 5- or 6-membered heterocyclyl ring,R² is hydrogen, C₃-C₈ cycloalkyl, C₁-C₇ alkyl, alkenyl, alkynyl, C₁-C₆haloalkyl, C₁-C₆ hydroxyalkyl, C₁-C₆ alkoxy, aryl, or heterocyclylhaving 1, 2, or 3 N, O, or S atoms,R³ is hydrogen or C₁-C₆ alkyl,R⁴ is selected from

wherein n is 0, 1, or 2,R⁵ is hydrogen or C₁-C₆ alkyl,R⁶ is hydrogen, halo, or C₁-C₆ alkyl, andRing A is 5 or 6-membered aryl or heterocyclyl, optionally substitutedby 1-3 R⁷ moieties, wherein R⁷ is H, alkyl, alkenyl, alkynyl, aryl,heterocyclyl, halo, cyano, nitro, OH, —O-alkyl, —O—(C₁-C₆ hydroxyalkyl),—O—(C₁-C₆ alkoxy), —O—(C₁-C₆ alkylene)-cyano, —O—(C₁-C₆alkylene)-C(O)R¹⁰, —OCHR¹⁰C(O)O—R¹¹, —OCHR¹⁰C(O)NHOH, —O—(C₁-C₆alkyl)-C(O)NR¹¹R¹², —O—(C₁-C₆ alkylene)-NR¹⁰C(O)R¹¹, —O—(C₁-C₆alkylene)-NR¹⁰C(O)OR¹¹, —O—(C₁-C₆ alkylene)-NR¹⁰C(O)NR¹¹R¹²,—OCHR¹⁰C(O)NR¹¹R¹², —O—(C₁-C₆ alkylene)-S(O)R¹⁰, —O—(C₁-C₆alkyl)-S(O)₂R¹⁰, —O—(C₁-C₆ alkylene)-S(O)₂NR¹¹R¹², —O—(C₁-C₆alkylene)-NR¹⁰S(O)₂NR¹¹R¹², —O—(C₁-C₆ alkylene)-NR¹⁰S(O)₂R¹¹, —O—(C₁-C₆alkylene)-S(O)₂R¹⁰, —O—(C₁-C₆ alkylene)-NR¹¹R¹², —(C₁-C₆alkylene)-S(O)₂R¹⁰, —(C₁-C₆ alkylene)-S(O)₂NR¹¹R¹², —(C₁-C₆alkylene)-S(O)R¹⁰, —(C₁-C₆ alkylene)-C(O)R¹⁰, —(C₁-C₆alkylene)-C(O)NR¹¹R¹², —(C₁-C₆ alkylene)-NR¹⁰C(O)R¹¹, —(C₁-C₆alkylene)-NR¹⁰S(O)₂R¹¹, —(C₁-C₆ alkylene)-NR¹⁰C(O)OR¹¹, —(C₁-C₆alkylene)-NR¹⁰C(O)NR¹¹R¹², —(C₁-C₆ alkylene)-NR¹⁰S(O)₂NR¹¹R¹², —(C₁-C₆alkylene)-C(O)OR¹⁰, —(C₁-C₆ alkylene)-NR¹¹R¹², —NR¹¹R¹², —NR¹¹C(O)R¹²,—NR¹⁰S(O)₂R¹¹, —NR¹⁰S(O)₂NR¹¹R¹², —C(O)R¹⁰, —S(O)R¹⁰, —S(O)₂R¹⁰, or—S(O)₂NR¹¹R¹², wherein R¹⁰, R¹¹, and R¹² are independently H, C₁-C₆alkyl, C₃-C₈ cycloalkyl, aryl, or heterocyclyl, or R¹⁰ and R¹¹ or R¹¹and R¹² combine with the atom(s) to which they are attached to form a 5-or 6-membered heterocyclyl ring,wherein the above alkyl, alkenyl, alkynyl, aryl, cycloalkyl, orheterocyclyl moieties provided in R¹, R², R⁷, R⁸, R⁹, R¹⁰, R¹¹, and R¹²are each optionally and independently substituted by 1-3 substituentsselected from

-   -   alkylamine,    -   amino,    -   aryl, cycloalkyl, heterocyclyl,    -   C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ hydroxyalkyl, C₁-C₆ alkoxy,        C₁-C₆ alkylamine, C₁-C₆ dialkylamine, C₂-C₆ alkenyl, or C₂-C₆        alkynyl, wherein each of which may be interrupted by one or more        hetero atoms,    -   carboxyl,    -   cyano,    -   halo,    -   hydroxy,    -   nitro,    -   oxo,    -   —C(O)OH, —C(O)₂—(C₁-C₆ alkyl), —C(O)₂—(C₃-C₈ cycloalkyl),        —C(O)₂-(aryl), —C(O)₂-(heterocyclyl), —C(O)₂—(C₁-C₆        alkylene)aryl, —C(O)₂—(C₁-C₆ alkylene)heterocyclyl,        —C(O)₂—(C₁-C₆ alkylene)cycloalkyl, —C(O)(C₁-C₆ alkyl),        —C(O)(C₃-C₈ cycloalkyl), —C(O)(aryl), —C(O)(heterocyclyl),        —C(O)(C₁-C₆ alkylene)aryl, —C(O)(C₁-C₆ alkylene)heterocyclyl,        and —C(O)(C₁-C₆ alkyl)cycloalkyl,        wherein each of the above optional substituents can be further        optionally substituted by 1-5 substituents selected from amino,        cyano, halo, hydroxy, nitro, C₁-C₆ alkylamine, C₁-C₆        dialkylamine, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, and        C₁-C₆ hydroxyalkyl, wherein each alkyl is optionally substituted        by one or more halo substituents, or a pharmaceutically        acceptable salt, hydrate, solvate, tautomer or stereoisomer        thereof.

In one embodiment, the invention relates to compounds of Formula Iwherein R¹ is selected from hydrogen, halo, cyano, hydroxyl, —NR⁸R⁹,C₃-C₈ cycloalkyl, C₁-C₆ alkyl, alkenyl, alkynyl, C₁-C₆ alkoxy, —(C₁-C₆alkylene)NR⁸R⁹, —C(O)OR⁸, —C(O)NR⁸R⁹, —C(O)R⁸, aryl, or heterocyclylhaving 1, 2, or 3 N, O, or S atoms, wherein R⁸ and R⁹ are independentlyH, C₁-C₆ alkyl, C₃-C₈ cycloalkyl, aryl, or heterocyclyl, or R⁸ and R⁹combine with the N atom to which they are attached to form a 5- or6-membered heterocyclyl ring.

In another embodiment, the invention relates to compounds of Formula Iwherein R¹ is selected from

wherein R¹³, R¹⁴ and R¹⁵ are independently selected from hydrogen,alkylamine, amino, aryl, cycloalkyl, heterocyclyl, C₁-C₆ alkyl, C₁-C₆alkoxy, carboxyl, cyano, halo, and hydroxyl, or R¹³ and R¹⁴ combine withthe N atom to which they are attached to form a 5- or 6-memberedheterocyclyl ring.

In a further embodiment, R¹ is selected from hydrogen, fluoro, cyano,and methyl.

In one embodiment, the invention relates to compounds of Formula Iwherein R² is selected from C₃-C₈ cycloalkyl, C₁-C₆ alkyl, alkenyl,alkynyl, aryl, and heterocyclyl having 1, 2, or 3 N, O, or S atoms,wherein the alkyl, alkenyl, alkynyl, aryl, cycloalkyl, or heterocyclylmoieties are each optionally and independently substituted by 1-3substituents selected from aryl, cycloalkyl, heterocyclyl, C₁-C₆ alkyl,C₁-C₆ alkoxy, C₁-C₆ alkylamine, C₂-C₆ alkenyl, or C₂-C₆ alkynyl, whereineach of which may be interrupted by one or more hetero atoms andoptionally substituted by cyano or halo.

In another embodiment, the invention relates to compounds of Formula Iwherein R² is selected from

wherein X is O or S and n=0, 1, or 2.

In a further embodiment, R² is selected from

In yet another embodiment, R² is selected from

In one embodiment, the invention relates to compounds of Formula Iwherein R³ and R⁵ are independently selected from hydrogen, methyl, andethyl.

In one embodiment, the invention relates to compounds of Formula Iwherein R⁶ is selected from hydrogen, fluoro, methyl, and ethyl.

In one embodiment, the invention relates to compounds of Formula Iwherein n is 2.

In one embodiment, the invention relates to compounds of Formula Iwherein Ring A is selected from

wherein X is S, O, NH, or —N(C₁-C₆ alkyl).

In another embodiment, Ring A is selected from

In a further embodiment, Ring A is

wherein R⁷ is hydrogen, —(C₁-C₆ alkylene)-S(O)₂NR¹¹R¹², —(C₁-C₆alkylene)-S(O)R¹⁰, —(C₁-C₆ alkylene)-S(O)₂R¹⁰, —NR¹⁰S(O)₂R¹¹, or—NR¹⁰S(O)₂NR¹¹R¹².

In a further embodiment, R⁷ is selected from

wherein n is an integer from 0 to 6, m is an integer from 1 to 6, R¹⁶,R¹⁷, and R¹⁸ are independently selected from hydrogen, C₁-C₆ alkyl,C₃-C₈ cycloalkyl, aryl, and heterocyclyl, or R¹⁶ and R¹⁷ or R¹⁷ and R¹⁸combine with the atom(s) to which they are attached to form a 5- or6-membered heterocyclyl ring, R¹⁹ is hydrogen, C₁-C₆ alkyl, C₃-C₈cycloalkyl —S(O)₂R¹⁰, or —S(O)₂NR¹¹R¹², wherein R¹⁰, R¹¹, and R¹² areindependently selected from hydrogen, C₁-C₆ alkyl, C₃-C₈ cycloalkyl,aryl, or heterocyclyl, or R¹¹ and R¹² combine with the N atom to whichthey are attached to form a 5- or 6-membered heterocyclyl ring.

In another embodiment, the invention relates to compounds selected from

The invention is also directed to pharmaceutically acceptable salts,hydrates, and solvates of the compounds of Formula I. Advantageousmethods of making the compounds of Formula I are also described.

In one aspect, the invention encompasses a method for treating orpreventing hepatitis C virus infection in a mammal in need thereof,preferably in a human in need thereof, comprising administering to thepatient a therapeutically or prophylactically effective amount of aFormula I compound. In one embodiment, the invention encompasses amethod for treating or preventing hepatitis C virus infection byadministering to a patient in need thereof a therapeutically orprophylactically effective amount of a Formula I compound that is aninhibitor of HCV NS5B polymerase.

In another aspect, the invention encompasses a method for treating orpreventing hepatitis C virus infection in a patient in need thereof,comprising administering to the patient a therapeutically orprophylactically effective amount of a compound of Formula I and apharmaceutically acceptable excipient, carrier, or vehicle.

In another aspect, the invention encompasses a method for treating orpreventing hepatitis C virus infection in a patient in need thereof,comprising administering to the patient a therapeutically orprophylactically effective amount of a compound of Formula I and anadditional therapeutic agent, preferably an additional antiviral agentor an immunomodulatory agent.

DETAILED DESCRIPTION OF THE INVENTION

Where the following terms are used in this specification, they are usedas defined below:

The terms “comprising,” “having” and “including” are used herein intheir open, non-limiting sense.

The term “alkyl”, as used herein, unless otherwise indicated, includessaturated monovalent hydrocarbon radicals having straight, branched, orcyclic moieties (including fused and bridged bicyclic and spirocyclicmoieties), or a combination of the foregoing moieties. For an alkylgroup to have cyclic moieties, the group must have at least three carbonatoms.

The term “alkylene”, as used herein, unless otherwise indicated,includes a divalent radical derived from alkyl, as exemplified by—CH₂CH₂CH₂CH₂—.

The term “alkenyl”, as used herein, unless otherwise indicated, includesalkyl moieties having at least one carbon-carbon double bond whereinalkyl is as defined above and including E and Z isomers of said alkenylmoiety.

The term “alkynyl”, as used herein, unless otherwise indicated, includesalkyl moieties having at least one carbon-carbon triple bond whereinalkyl is as defined above.

The term “alkoxy”, as used herein, unless otherwise indicated, includesO-alkyl groups wherein alkyl is as defined above.

The term “Me” means methyl, “Et” means ethyl, and “Ac” means acetyl.

The term “cycloalkyl”, as used herein, unless otherwise indicated refersto a non-aromatic, saturated or partially saturated, monocyclic orfused, spiro or unfused bicyclic or tricyclic hydrocarbon referred toherein containing a total of from 3 to 10 carbon atoms, preferably 5-8ring carbon atoms. Exemplary cycloalkyls include monocyclic rings havingfrom 3-7, preferably 3-6, carbon atoms, such as cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl and the like. Illustrative examplesof cycloalkyl are derived from, but not limited to, the following:

The term “aryl”, as used herein, unless otherwise indicated, includes anorganic radical derived from an aromatic hydrocarbon by removal of onehydrogen, such as phenyl or naphthyl.

The term “heterocyclic” or “heterocyclyl”, as used herein, unlessotherwise indicated, includes aromatic (e.g., heteroaryls) andnon-aromatic heterocyclic groups containing one to four heteroatoms eachselected from O, S and N, wherein each heterocyclic group has from 4-10atoms in its ring system, and with the proviso that the ring of saidgroup does not contain two adjacent O atoms. Non-aromatic heterocyclicgroups include groups having only 3 atoms in their ring system, butaromatic heterocyclic groups must have at least 5 atoms in their ringsystem. The heterocyclic groups include benzo-fused ring systems. Anexample of a 4 membered heterocyclic group is azetidinyl (derived fromazetidine). An example of a 5 membered heterocyclic group is thiazolyland an example of a 10 membered heterocyclic group is quinolinyl.Examples of non-aromatic heterocyclic groups are pyrrolidinyl,tetrahydrofuranyl, dihydrofuranyl, tetrahydrothienyl, tetrahydropyranyl,dihydropyranyl, tetrahydrothiopyranyl, piperidino, morpholino,thiomorpholino, thioxanyl, piperazinyl, azetidinyl, oxetanyl, thietanyl,homopiperidinyl, oxepanyl, thiepanyl, oxazepinyl, diazepinyl,thiazepinyl, 1,2,3,6-tetrahydropyridinyl, 2-pyrrolinyl, 3-pyrrolinyl,indolinyl, 2H-pyranyl, 4H-pyranyl, dioxanyl, 1,3-dioxolanyl,pyrazolinyl, dithianyl, dithiolanyl, dihydropyranyl, dihydrothienyl,dihydrofuranyl, pyrazolidinyl, imidazolinyl, imidazolidinyl,3-azabicyclo[3.1.0]hexanyl, 3-azabicyclo[4.1.0]heptanyl, 3H-indolyl andquinolizinyl. Examples of aromatic heterocyclic groups are pyridinyl,imidazolyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl,furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl,quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzofuranyl,cinnolinyl, indazolyl, indolizinyl, phthalazinyl, pyridazinyl,triazinyl, isoindolyl, pteridinyl, purinyl, oxadiazolyl, thiadiazolyl,furazanyl, benzofurazanyl, benzothiophenyl, benzothiazolyl,benzoxazolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, andfuropyridinyl. The foregoing groups, as derived from the groups listedabove, may be C-attached or N-attached where such is possible. Forinstance, a group derived from pyrrole may be pyrrol-1-yl (N-attached)or pyrrol-3-yl (C-attached). Further, a group derived from imidazole maybe imidazol-1-yl (N-attached) or imidazol-3-yl (C-attached). The 4-10membered heterocyclic may be optionally substituted on any ring carbon,sulfur, or nitrogen atom(s) by one to two oxo, per ring. An example of aheterocyclic group wherein 2 ring carbon atoms are substituted with oxomoieties is 1,1-dioxo-thiomorpholinyl. Other illustrative examples of4-10 membered heterocyclic are derived from, but not limited to, thefollowing:

Unless defined otherwise, “alkyl,” “alkylene,” “alkenyl,” “alkynyl,”“aryl,” “cycloalkyl,” or “heterocyclyl” are each optionally andindependently substituted by 1-3 substituents selected from alkylamine,amino, aryl, cycloalkyl, heterocyclyl, C₁-C₆ alkyl, C₁-C₆ haloalkyl,C₁-C₆ hydroxyalkyl, C₁-C₆ alkoxy, C₁-C₆ alkylamine, C₁-C₆ dialkylamine,C₂-C₆ alkenyl, or C₂-C₆ alkynyl, wherein each of which may beinterrupted by one or more hetero atoms, carboxyl, cyano, halo, hydroxy,nitro, —C(O)OH, —C(O)₂—(C₁-C₆ alkyl), —C(O)₂—(C₃-C₈ cycloalkyl),—C(O)₂-(aryl), —C(O)₂-(heterocyclyl), —C(O)₂—(C₁-C₆ alkylene)aryl,—C(O)₂—(C₁-C₆ alkylene)heterocyclyl, —C(O)₂—(C₁-C₆ alkylene)cycloalkyl,—C(O)(C₁-C₆ alkyl), —C(O)(C₃-C₈ cycloalkyl), —C(O)(aryl),—C(O)(heterocyclyl), —C(O)(C₁-C₆ alkylene)aryl, —C(O)(C₁-C₆alkylene)heterocyclyl, and —C(O)(C₁-C₆ alkylene)cycloalkyl, wherein eachof these optional substituents can be further optionally substituted by1-5 substituents selected from amino, cyano, halo, hydroxy, nitro, C₁-C₆alkylamine, C₁-C₆ dialkylamine, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆alkenyl, and C₁-C₆ hydroxyalkyl, wherein each alkyl is optionallysubstituted by one or more halo substituents, e.g., CF₃.

The term “immunomodulator” refers to natural or synthetic productscapable of modifying the normal or aberrant immune system throughstimulation or suppression.

The term “preventing” refers to the ability of a compound or compositionof the invention to prevent a disease identified herein in patientsdiagnosed as having the disease or who are at risk of developing suchdisease. The term also encompasses preventing further progression of thedisease in patients who are already suffering from or have symptoms ofsuch disease.

The term “patient” or “subject” means an animal (e.g., cow, horse,sheep, pig, chicken, turkey, quail, cat, dog, mouse, rat, rabbit, guineapig, etc.) or a mammal, including chimeric and transgenic animals andmammals. In the treatment or prevention of HCV infection, the term“patient” or “subject” preferably means a monkey or a human, mostpreferably a human. In a specific embodiment the patient or subject isinfected by or exposed to the hepatitis C virus. In certain embodiments,the patient is a human infant (age 0-2), child (age 2-17), adolescent(age 12-17), adult (age 18 and up) or geriatric (age 70 and up) patient.In addition, the patient includes immunocompromised patients such as HIVpositive patients, cancer patients, patients undergoing immunotherapy orchemotherapy. In a particular embodiment, the patient is a healthyindividual, i.e., not displaying symptoms of other viral infections.

The term a “therapeutically effective amount” refers to an amount of thecompound of the invention sufficient to provide a benefit in thetreatment or prevention of viral disease, to delay or minimize symptomsassociated with viral infection or viral-induced disease, or to cure orameliorate the disease or infection or cause thereof. In particular, atherapeutically effective amount means an amount sufficient to provide atherapeutic benefit in vivo. Used in connection with an amount of acompound of the invention, the term preferably encompasses a non-toxicamount that improves overall therapy, reduces or avoids symptoms orcauses of disease, or enhances the therapeutic efficacy of or synergieswith another therapeutic agent.

The term a “prophylactically effective amount” refers to an amount of acompound of the invention or other active ingredient sufficient toresult in the prevention of infection, recurrence or spread of viralinfection. A prophylactically effective amount may refer to an amountsufficient to prevent initial infection or the recurrence or spread ofthe infection or a disease associated with the infection. Used inconnection with an amount of a compound of the invention, the termpreferably encompasses a non-toxic amount that improves overallprophylaxis or enhances the prophylactic efficacy of or synergies withanother prophylactic or therapeutic agent.

The term “in combination” refers to the use of more than oneprophylactic and/or therapeutic agents simultaneously or sequentiallyand in a manner that their respective effects are additive orsynergistic.

The term “treating” refers to:

(i) preventing a disease, disorder, or condition from occurring in ananimal that may be predisposed to the disease, disorder and/orcondition, but has not yet been diagnosed as having it;

(ii) inhibiting the disease, disorder, or condition, i.e., arresting itsdevelopment; and

(iii) relieving the disease, disorder, or condition, i.e., causingregression of the disease, disorder, and/or condition.

The terms “R” and “S” indicate the specific stereochemical configurationof a substituent at an asymmetric carbon atom in a chemical structure asdrawn.

The term “rac” indicates that a compound is a racemate, which is definedas an equimolar mixture of a pair of enantiomers. A “rac” compound doesnot exhibit optical activity. The chemical name or formula of a racemateis distinguished from those of the enantiomers by the prefix (±)- orrac- (or racem-) or by the symbols RS and SR.

The compounds of the invention may exhibit the phenomenon oftautomerism. While Formula I cannot expressly depict all possibletautomeric forms, it is to be understood that Formula I is intended torepresent any tautomeric form of the depicted compound and is not to belimited merely to a specific compound form depicted by the formuladrawings. For illustration, and in no way limiting the range oftautomers, the compounds of Formula I may exist as the following:

Some of the inventive compounds may exist as single stereoisomers (i.e.,essentially free of other stereoisomers), racemates, and/or mixtures ofenantiomers and/or diastereomers. All such single stereoisomers,racemates and mixtures thereof are intended to be within the scope ofthe present invention. Preferably, the inventive compounds that areoptically active are used in optically pure form.

As generally understood by those skilled in the art, an optically purecompound having one chiral center (i.e., one asymmetric carbon atom) isone that consists essentially of one of the two possible enantiomers(i.e., is enantiomerically pure), and an optically pure compound havingmore than one chiral center is one that is both diastereomerically pureand enantiomerically pure. Preferably, the compounds of the presentinvention are used in a form that is at least 90% free of otherenantiomers or diastereomers of the compounds, that is, a form thatcontains at least 90% of a single isomer (80% enantiomeric excess(“e.e.”) or diastereomeric excess (“d.e.”)), more preferably at least95% (90% e.e. or d.e.), even more preferably at least 97.5% (95% e.e. ord.e.), and most preferably at least 99% (98% e.e. or d.e.).

Additionally, the Formula I is intended to cover solvated as well asunsolvated forms of the identified structures. For example, Formula Iincludes compounds of the indicated structure in both hydrated andnon-hydrated forms. Other examples of solvates include the structures incombination with isopropanol, ethanol, methanol, DMSO, ethyl acetate,acetic acid, or ethanolamine.

In addition to compounds of Formula I, the invention includespharmaceutically acceptable prodrugs, pharmaceutically activemetabolites, and pharmaceutically acceptable salts of such compounds andmetabolites.

“A pharmaceutically acceptable prodrug” is a compound that may beconverted under physiological conditions or by solvolysis to thespecified compound or to a pharmaceutically acceptable salt of suchcompound prior to exhibiting its pharmacological effect (s). Typically,the prodrug is formulated with the objective(s) of improved chemicalstability, improved patient acceptance and compliance, improvedbioavailability, prolonged duration of action, improved organselectivity, improved formulation (e.g., increased hydrosolubility),and/or decreased side effects (e.g., toxicity). The prodrug can bereadily prepared from the compounds of Formula I using methods known inthe art, such as those described by Burger's Medicinal Chemistry andDrug Chemistry, 1, 172-178, 949-982 (1995). See also Bertolini et al.,J. Med. Chem., 40, 2011-2016 (1997); Shan, et al., J. Pharm. Sci., 86(7), 765-767; Bagshawe, Drug Dev. Res., 34, 220-230 (1995); Bodor,Advances in Drug Res., 13, 224-331 (1984); Bundgaard, Design of Prodrugs(Elsevier Press 1985); Larsen, Design and Application of Prodrugs, DrugDesign and Development (Krogsgaard-Larsen et al., eds., Harwood AcademicPublishers, 1991); Dear et al., J. Chromatogr. B, 748, 281-293 (2000);Spraul et al., J. Pharmaceutical & Biomedical Analysis, 10, 601-605(1992); and Prox et al., Xenobiol., 3, 103-112 (1992).

“A pharmaceutically active metabolite” is intended to mean apharmacologically active product produced through metabolism in the bodyof a specified compound or salt thereof. After entry into the body, mostdrugs are substrates for chemical reactions that may change theirphysical properties and biologic effects. These metabolic conversions,which usually affect the polarity of the Formula I compounds, alter theway in which drugs are distributed in and excreted from the body.However, in some cases, metabolism of a drug is required for therapeuticeffect. For example, anticancer drugs of the anti-metabolite class mustbe converted to their active forms after they have been transported intoa cancer cell.

Since most drugs undergo metabolic transformation of some kind, thebiochemical reactions that play a role in drug metabolism may benumerous and diverse. The main site of drug metabolism is the liver,although other tissues may also participate.

A feature characteristic of many of these transformations is that themetabolic products, or “metabolites,” are more polar than the parentdrugs, although a polar drug does sometime yield a less polar product.Substances with high lipid/water partition coefficients, which passeasily across membranes, also diffuse back readily from tubular urinethrough the renal tubular cells into the plasma. Thus, such substancestend to have a low renal clearance and a long persistence in the body.If a drug is metabolized to a more polar compound, one with a lowerpartition coefficient, its tubular reabsorption will be greatly reduced.Moreover, the specific secretory mechanisms for anions and cations inthe proximal renal tubules and in the parenchymal liver cells operateupon highly polar substances.

As a specific example, phenacetin (acetophenetidin) and acetanilide areboth mild analgesic and antipyretic agents, but are transformed withinthe body to a more polar and more effective metabolite,p-hydroxyacetanilid (acetaminophen), which is widely used today. When adose of acetanilide is given to a person, the successive metabolitespeak and decay in the plasma sequentially. During the first hour,acetanilide is the principal plasma component. In the second hour, asthe acetanilide level falls, the metabolite acetaminophen concentrationreaches a peak. Finally, after a few hours, the principal plasmacomponent is a further metabolite that is inert and can be excreted fromthe body. Thus, the plasma concentrations of one or more metabolites, aswell as the drug itself, can be pharmacologically important.

“A pharmaceutically acceptable salt” is intended to mean a salt thatretains the biological effectiveness of the free acids and bases of thespecified compound and that is not biologically or otherwiseundesirable. A compound of the invention may possess a sufficientlyacidic, a sufficiently basic, or both functional groups, and accordinglyreact with any of a number of inorganic or organic bases, and inorganicand organic acids, to form a pharmaceutically acceptable salt. Exemplarypharmaceutically acceptable salts include those salts prepared byreaction of the compounds of the present invention with a mineral ororganic acid or an inorganic base, such as salts including sulfates,pyrosulfates, bisulfates, sulfites, bisulfites, phosphates,monohydrogenphosphates, dihydrogenphosphates, metaphosphates,pyrophosphates, chlorides, bromides, iodides, acetates, propionates,decanoates, caprylates, acrylates, formates, isobutyrates, caproates,heptanoates, propiolates, oxalates, malonates, succinates, suberates,sebacates, fumarates, maleates, butyne-1,4-dioates, hexyne-1,6-dioates,benzoates, chlorobenzoates, methylbenzoates, dinitrobenzoates,hydroxybenzoates, methoxybenzoates, phthalates, sulfonates,xylenesulfonates, phenylacetates, phenylpropionates, phenylbutyrates,citrates, lactates, γ-hydroxybutyrates, glycolates, tartrates,methane-sulfonates, propanesulfonates, naphthalene-1-sulfonates,naphthalene-2-sulfonates, and mandelates.

If the inventive compound is a base, the desired pharmaceuticallyacceptable salt may be prepared by any suitable method available in theart, for example, treatment of the free base with an inorganic acid,such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid,phosphoric acid and the like, or with an organic acid, such as aceticacid, maleic acid, succinic acid, mandelic acid, fumaric acid, malonicacid, pyruvic acid, oxalic acid, glycolic acid, salicylic acid, apyranosidyl acid, such as glucuronic acid or galacturonic acid, anα-hydroxy acid, such as citric acid or tartaric acid, an amino acid,such as aspartic acid or glutamic acid, an aromatic acid, such asbenzoic acid or cinnamic acid, a sulfonic acid, such asp-toluenesulfonic acid or ethanesulfonic acid, or the like.

If the inventive compound is an acid, the desired pharmaceuticallyacceptable salt may be prepared by any suitable method, for example,treatment of the free acid with an inorganic or organic base, such as anamine (primary, secondary or tertiary), an alkali metal hydroxide oralkaline earth metal hydroxide, or the like. Illustrative examples ofsuitable salts include organic salts derived from amino acids, such asglycine and arginine, ammonia, primary, secondary, and tertiary amines,and cyclic amines, such as piperidine, morpholine and piperazine, andinorganic salts derived from sodium, calcium, potassium, magnesium,manganese, iron, copper, zinc, aluminum and lithium.

In the case of agents that are solids, it is understood by those skilledin the art that the inventive compounds and salts may exist in differentcrystal or polymorphic forms, all of which are intended to be within thescope of the present invention and specified formulas.

Methods of Treatment and Prevention of Hepatitis C Viral Infections

The present invention provides methods for treating or preventing ahepatitis C virus infection in a patient in need thereof.

The present invention further provides methods for introducing atherapeutically effective amount of the Formula I compound orcombination of such compounds into the blood stream of a patient in thetreatment and/or prevention of hepatitis C viral infections.

The magnitude of a prophylactic or therapeutic dose of a Formula Icompound of the invention or a pharmaceutically acceptable salt,solvate, or hydrate, thereof in the acute or chronic treatment orprevention of an infection will vary, however, with the nature andseverity of the infection, and the route by which the active ingredientis administered. The dose, and in some cases the dose frequency, willalso vary according to the infection to be treated, the age, bodyweight, and response of the individual patient. Suitable dosing regimenscan be readily selected by those skilled in the art with dueconsideration of such factors.

The methods of the present invention are particularly well suited forhuman patients. In particular, the methods and doses of the presentinvention can be useful for immunocompromised patients including, butnot limited to cancer patients, HIV infected patients, and patients withan immunodegenerative disease. Furthermore, the methods can be usefulfor immunocompromised patients currently in a state of remission. Themethods and doses of the present invention are also useful for patientsundergoing other antiviral treatments. The prevention methods of thepresent invention are particularly useful for patients at risk of viralinfection. These patients include, but are not limited to health careworkers, e.g., doctors, nurses, hospice care givers; military personnel;teachers; childcare workers; patients traveling to, or living in,foreign locales, in particular third world locales including social aidworkers, missionaries, and foreign diplomats. Finally, the methods andcompositions include the treatment of refractory patients or patientsresistant to treatment such as resistance to reverse transcriptaseinhibitors, protease inhibitors, etc.

Doses

Toxicity and efficacy of the compounds of the invention can bedetermined by standard pharmaceutical procedures in cell cultures orexperimental animals, e.g., for determining the LD₅₀ (the dose lethal to50% of the population) and the ED₅₀ (the dose therapeutically effectivein 50% of the population). The dose ratio between toxic and therapeuticeffects is the therapeutic index and it can be expressed as the ratioLD₅₀/ED₅₀.

The data obtained from the cell culture assays and animal studies can beused in formulating a range of dosage of the compounds for use inhumans. The dosage of such compounds lie preferably within a range ofcirculating concentrations that include the ED₅₀ with little or notoxicity. The dosage may vary within this range depending upon thedosage form employed and the route of administration utilized. For anycompound used in the method of the invention, the therapeuticallyeffective dose can be estimated initially from cell culture assays. Adose may be formulated in animal models to achieve a circulating plasmaconcentration range that includes the IC₅₀ (i.e., the concentration ofthe test compound that achieves a half-maximal inhibition of symptoms)as determined in cell culture; alternatively, the dose of the Formula Icompound may be formulated in animal models to achieve a circulatingplasma concentration range of the compound that corresponds to theconcentration required to achieve a fixed magnitude of response. Suchinformation can be used to more accurately determine useful doses inhumans. Levels in plasma may be measured, for example, by highperformance liquid chromatography.

The protocols and compositions of the invention are preferably tested invitro, and then in vivo, for the desired therapeutic or prophylacticactivity, prior to use in humans. For example, in vitro assays which canbe used to determine whether administration of a specific therapeuticprotocol is indicated, include in vitro cell culture assays in whichcells that are responsive to the effects of the Formula I compounds areexposed to the ligand and the magnitude of response is measured by anappropriate technique. The assessment of the Formula I compound is thenevaluated with respect to the Formula I compound potency, and the degreeof conversion of the Formula I compound prodrug. Compounds for use inmethods of the invention can be tested in suitable animal model systemsprior to testing in humans, including but not limited to in rats, mice,chicken, cows, monkeys, rabbits, hamsters, etc. The compounds can thenbe used in the appropriate clinical trials.

The magnitude of a prophylactic or therapeutic dose of a prodrug of aFormula I compound of the invention or a pharmaceutically acceptablesalt, solvate, or hydrate thereof in the acute or chronic treatment orprevention of an infection or condition will vary with the nature andseverity of the infection, and the route by which the active ingredientis administered. The dose, and perhaps the dose frequency, will alsovary according to the infection to be treated, the age, body weight, andresponse of the individual patient. Suitable dosing regimens can bereadily selected by those skilled in the art with due consideration ofsuch factors. In one embodiment, the dose administered depends upon thespecific compound to be used, and the weight and condition of thepatient. Also, the dose may differ for various particular Formula Icompounds; suitable doses can be predicted on the basis of theaforementioned in vitro measurements and on the basis of animal studies,such that smaller doses will be suitable for those Formula I compoundsthat show effectiveness at lower concentrations than other Formula Icompounds when measured in the systems described or referenced herein.In general, the dose per day is in the range of from about 0.001 to 100mg/kg, preferably about 1 to 25 mg/kg, more preferably about 5 to 15mg/kg. For treatment of humans infected by hepatitis C viruses, about0.1 mg to about 15 g per day is administered in about one to fourdivisions a day, preferably 100 mg to 12 g per day, more preferably from100 mg to 8000 mg per day.

Additionally, the recommended daily dose ran can be administered incycles as single agents or in combination with other therapeutic agents.In one embodiment, the daily dose is administered in a single dose or inequally divided doses. In a related embodiment, the recommended dailydose can be administered once time per week, two times per week, threetimes per week, four times per week or five times per week.

In one embodiment, the compounds of the invention are administered toprovide systemic distribution of the compound within the patient. In arelated embodiment, the compounds of the invention are administered toproduce a systemic effect in the body.

In another embodiment the compounds of the invention are administeredvia oral, mucosal (including sublingual, buccal, rectal, nasal, orvaginal), parenteral (including subcutaneous, intramuscular, bolusinjection, intraarterial, or intravenous), transdermal, or topicaladministration. In a specific embodiment the compounds of the inventionare administered via mucosal (including sublingual, buccal, rectal,nasal, or vaginal), parenteral (including subcutaneous, intramuscular,bolus injection, intraarterial, or intravenous), transdermal, or topicaladministration. In a further specific embodiment, the compounds of theinvention are administered via oral administration. In a furtherspecific embodiment, the compounds of the invention are not administeredvia oral administration.

Different therapeutically effective amounts may be applicable fordifferent infections, as will be readily known by those of ordinaryskill in the art. Similarly, amounts sufficient to treat or prevent suchinfections, but insufficient to cause, or sufficient to reduce, adverseeffects associated with conventional therapies are also encompassed bythe above described dosage amounts and dose frequency schedules.

Combination Therapy

Specific methods of the invention further comprise the administration ofan additional therapeutic agent (i.e., a therapeutic agent other than acompound of the invention). In certain embodiments of the presentinvention, the compounds of the invention can be used in combinationwith at least one other therapeutic agent. Therapeutic agents include,but are not limited to antibiotics, antiemetic agents, antidepressants,and antifungal agents, anti-inflammatory agents, antiviral agents,anticancer agents, immunomodulatory agents, α-interferons,β-interferons, ribavirin, alkylating agents, hormones, cytokines, ortoll receptor-like modulators. In one embodiment the inventionencompasses the administration of an additional therapeutic agent thatis HCV specific or demonstrates anti-HCV activity.

The Formula I compounds of the invention can be administered orformulated in combination with antibiotics. For example, they can beformulated with a macrolide (e.g., tobramycin (Tobi®)), a cephalosporin(e.g., cephalexin (Keflex®), cephradine (Velosef®), cefuroxime(Ceftin®), cefprozil (Cefzil®), cefaclor (Ceclor®), cefixime (Suprax®)or cefadroxil (Duricef®)), a clarithromycin (e.g., clarithromycin(Biaxin®)), an erythromycin (e.g. erythromycin (EMycin®)), a penicillin(e.g., penicillin V (V-Cillin K® or Pen Vee K®)) or a quinolone (e.g.,ofloxacin (Floxin®), ciprofloxacin (Cipro®) or norfloxacin (Noroxin®)),aminoglycoside antibiotics (e.g., apramycin, arbekacin, bambermycins,butirosin, dibekacin, neomycin, neomycin, undecylenate, netilmicin,paromomycin, ribostamycin, sisomicin, and spectinomycin), amphenicolantibiotics (e.g., azidamfenicol, chloramphenicol, florfenicol, andthiamphenicol), ansamycin antibiotics (e.g., rifamide and rifampin),carbacephems (e.g., loracarbef), carbapenems (e.g., biapenem andimipenem), cephalosporins (e.g., cefaclor, cefadroxil, cefamandole,cefatrizine, cefazedone, cefozopran, cefpimizole, cefpiramide, andcefpirome), cephamycins (e.g., cefbuperazone, cefmetazole, andcefminox), monobactams (e.g., aztreonam, carumonam, and tigemonam),oxacephems (e.g. flomoxef, and moxalactam), penicillins (e.g.,amdinocillin, amdinocillin pivoxil, amoxicillin, bacampicillin,benzylpenicillinic acid, benzylpenicillin sodium, epicillin,fenbenicillin, floxacillin, penamccillin, penethamate hydriodide,penicillin o-benethamine, penicillin 0, penicillin V, penicillin Vbenzathine, penicillin V hydrabamine, penimepicycline, andphencihicillin potassium), lincosamides (e.g., clindamycin, andlincomycin), amphomycin, bacitracin, capreomycin, colistin, enduracidin,enviomycin, tetracyclines (e.g., apicycline, chlortetracycline,clomocycline, and demeclocycline), 2,4-diaminopyrimidines (e.g.,brodimoprim), nitrofurans (e.g., furaltadone, and furazolium chloride),quinolones and analogs thereof (e.g., cinoxacin, clinafloxacin,flumequine, and grepagloxacin), sulfonamides (e.g., acetylsulfamethoxypyrazine, benzylsulfamide, noprylsulfamide,phthalylsulfacetamide, sulfachrysoidine, and sulfacytine), sulfones(e.g., diathymosulfone, glucosulfone sodium, and solasulfone),cycloserine, mupirocin and tuberin.

The Formula I compounds of the invention can also be administered orformulated in combination with an antiemetic agent. Suitable antiemeticagents include, but are not limited to, metoclopromide, domperidone,prochlorperazine, promethazine, chlorpromazine, trimethobenzamide,ondansetron, granisetron, hydroxyzine, acethylleucine monoethanolamine,alizapride, azasetron, benzquinamide, bietanautine, bromopride,buclizine, clebopride, cyclizine, dimenhydrinate, diphenidol,dolasetron, meclizine, methallatal, metopimazine, nabilone, oxyperndyl,pipamazine, scopolamine, sulpiride, tetrahydrocannabinols,thiethylperazine, thioproperazine, tropisetron, and mixtures thereof.

The Formula I compounds of the invention can be administered orformulated in combination with an antidepressant. Suitableantidepressants include, but are not limited to, binedaline, caroxazone,citalopram, dimethazan, fencamine, indalpine, indeloxazinehydrocholoride, nefopam, nomifensine, oxitriptan, oxypertine,paroxetine, sertraline, thiazesim, trazodone, benmoxine, iproclozide,iproniazid, isocarboxazid, nialamide, octamoxin, phenelzine, cotinine,rolicyprine, rolipram, maprotiline, metralindole, mianserin,mirtazepine, adinazolam, amitriptyline, amitriptylinoxide, amoxapine,butriptyline, clomipramine, demexiptiline, desipramine, dibenzepin,dimetacrine, dothiepin, doxepin, fluacizine, imipramine, imipramineN-oxide, iprindole, lofepramine, melitracen, metapramine, nortriptyline,noxiptilin, opipramol, pizotyline, propizepine, protriptyline,quinupramine, tianeptine, trimipramine, adrafinil, benactyzine,bupropion, butacetin, dioxadrol, duloxetine, etoperidone, febarbamate,femoxetine, fenpentadiol, fluoxetine, fluvoxamine, hematoporphyrin,hypericin, levophacetoperane, medifoxamine, milnacipran, minaprine,moclobemide, nefazodone, oxaflozane, piberaline, prolintane,pyrisuccideanol, ritanserin, roxindole, rubidium chloride, sulpiride,tandospirone, thozalinone, tofenacin, toloxatone, tranylcypromine,L-tryptophan, venlafaxine, viloxazine, and zimeldine.

The Formula I compounds of the invention can be administered orformulated in combination with an antifungal agent. Suitable antifungalagents include but are not limited to amphotericin B, itraconazole,ketoconazole, fluconazole, intrathecal, flucytosine, miconazole,butoconazole, clotrimazole, nystatin, terconazole, tioconazole,ciclopirox, econazole, haloprogrin, naftifine, terbinafine,undecylenate, and griseofulvin.

The Formula I compounds of the invention can be administered orformulated in combination with an anti-inflammatory agent. Usefulanti-inflammatory agents include, but are not limited to, non-steroidalanti-inflammatory drugs such as salicylic acid, acetylsalicylic acid,methyl salicylate, diflunisal, salsalate, olsalazine, sulfasalazine,acetaminophen, indomethacin, sulindac, etodolac, mefenamic acid,meclofenamate sodium, tolmetin, ketorolac, dichlofenac, ibuprofen,naproxen, naproxen sodium, fenoprofen, ketoprofen, flurbinprofen,oxaprozin, piroxicam, meloxicam, ampiroxicam, droxicam, pivoxicam,tenoxicam, nabumetome, phenylbutazone, oxyphenbutazone, antipyrine,aminopyrine, apazone and nimesulide; leukotriene antagonists including,but not limited to, zileuton, aurothioglucose, gold sodium thiomalateand auranofin; steroids including, but not limited to, alclometasonediproprionate, amcinonide, beclomethasone dipropionate, betametasone,betamethasone benzoate, betamethasone diproprionate, betamethasonesodium phosphate, betamethasone valerate, clobetasol proprionate,clocortolone pivalate, hydrocortisone, hydrocortisone derivatives,desonide, desoximatasone, dexamethasone, flunisolide, flucoxinolide,flurandrenolide, halcinocide, medrysone, methylprednisolone,methprednisolone acetate, methylprednisolone sodium succinate,mometasone furoate, paramethasone acetate, prednisolone, prednisoloneacetate, prednisolone sodium phosphate, prednisolone tebuatate,prednisone, triamcinolone, triamcinolone acetonide, triamcinolonediacetate, and triamcinolone hexacetonide; and other anti-inflammatoryagents including, but not limited to, methotrexate, colchicine,allopurinol, probenecid, sulfinpyrazone and benzbromarone.

The Formula I compounds of the invention can be administered orformulated in combination with another antiviral agent. Useful antiviralagents include, but are not limited to, protease inhibitors, nucleosidereverse transcriptase inhibitors, non-nucleoside reverse transcriptaseinhibitors and nucleoside analogs. The antiviral agents include but arenot limited to zidovudine, acyclovir, gangcyclovir, vidarabine,idoxuridine, trifluridine, levovirin, viramidine and ribavirin, as wellas foscarnet, amantadine, rimantadine, saquinavir, indinavir,amprenavir, lopinavir, ritonavir, the α-interferons; β-interferons;adefovir, clevadine, entecavir, pleconaril.

The Formula I compounds of the invention can be administered orformulated in combination with an immunomodulatory agent.Immunomodulatory agents include, but are not limited to, methothrexate,leflunomide, cyclophosphamide, cyclosporine A, mycophenolate mofetil,rapamycin (sirolimus), mizoribine, deoxyspergualin, brequinar,malononitriloamindes (e.g., leflunamide), T cell receptor modulators,and cytokine receptor modulators, peptide mimetics, and antibodies(e.g., human, humanized, chimeric, monoclonal, polyclonal, Fvs, ScFvs,Fab or F(ab)2 fragments or epitope binding fragments), nucleic acidmolecules (e.g., antisense nucleic acid molecules and triple helices),small molecules, organic compounds, and inorganic compounds. Examples ofT cell receptor modulators include, but are not limited to, anti-T cellreceptor antibodies (e.g., anti-CD4 antibodies (e.g., cM-T412(Boehringer), IDEC-CE9.1® (IDEC and SKB), mAB 4162W94, Orthoclone andOKTcdr4a (Janssen-Cilag)), anti-CD3 antibodies (e.g., Nuvion (ProductDesign Labs), OKT3 (Johnson & Johnson), or Rituxan (IDEC)), anti-CD5antibodies (e.g., an anti-CD5 ricin-linked immunoconjugate), anti-CD7antibodies (e.g., CHH-380 (Novartis)), anti-CD8 antibodies, anti-CD40ligand monoclonal antibodies (e.g., IDEC-131 (IDEC)), anti-CD52antibodies (e.g., CAMPATH 1H (Ilex)), anti-CD2 antibodies, anti-CD11aantibodies (e.g., Xanelim (Genentech)), anti-B7 antibodies (e.g.,IDEC-114 (IDEC)), CTLA4-immunoglobulin, and toll receptor-like (TLR)modulators. Examples of cytokine receptor modulators include, but arenot limited to, soluble cytokine receptors (e.g., the extracellulardomain of a TNF-α receptor or a fragment thereof, the extracellulardomain of an IL-1β receptor or a fragment thereof, and the extracellulardomain of an IL-6 receptor or a fragment thereof), cytokines orfragments thereof (e.g., interleukin (IL)-2, IL-3, IL-4, IL-5, IL-6,IL-7, IL-8, IL-9, IL-10, IL-11, IL-12, IL-15, TNF-α, interferon (IFN)-α,IFN-β, IFN-γ, and GM-CSF), anti-cytokine receptor antibodies (e.g.,anti-IFN receptor antibodies, anti-IL-2 receptor antibodies (e.g.,Zenapax (Protein Design Labs)), anti-IL-4 receptor antibodies, anti-IL-6receptor antibodies, anti-IL-10 receptor antibodies, and anti-IL-12receptor antibodies), anti-cytokine antibodies (e.g., anti-IFNantibodies, anti-TNF-α antibodies, anti-IL-1β antibodies, anti-IL-6antibodies, anti-IL-8 antibodies (e.g., ABX-IL-8 (Abgenix)), andanti-IL-12 antibodies).

The Formula I compounds of the invention can be administered orformulated in combination with an agent which inhibits viral enzymes,including but not limited to inhibitors of HCV protease, such as BILN2061, SCH-503034, ITMN-191 or VX-950; and inhibitors of NS5B polymerasesuch as NM107 (and its prodrug NM283), R1626, R7078, BILN1941,GSK625433, GILD9128 or HCV-796.

The Formula I compounds of the invention can be administered orformulated in combination with an agent which inhibits HCV polymerasesuch as those described in Wu, Curr Drug Targets Infect Disord., 3,207-19 (2003) or in combination with compounds that inhibit the helicasefunction of the virus such as those described in Bretner M., et al.,Nucleosides Nucleotides Nucleic Acids., 22, 1531 (2003), or withinhibitors of other HCV specific targets such as those described inZhang X., IDrugs, 5(2), 154-8 (2002).

The Formula I compounds of the invention can be administered orformulated in combination with an agent which inhibits viralreplication.

The Formula I compounds of the invention can be administered orformulated in combination with cytokines. Examples of cytokines include,but are not limited to, interleukin-2 (IL-2), interleukin-3 (IL-3),interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-6 (IL-6),interleukin-7 (IL-7), interleukin-9 (IL-9), interleukin-10 (IL-10),interleukin-12 (IL-12), interleukin 15 (IL-15), interleukin 18 (IL-18),platelet derived growth factor (PDGF), erythropoietin (Epo), epidermalgrowth factor (EGF), fibroblast growth factor (FGF), granulocytemacrophage stimulating factor (GM-CSF), granulocyte colony stimulatingfactor (G-CSF), macrophage colony stimulating factor (M-CSF), prolactin,and interferon (IFN), e.g., IFN-α, and IFN-γ).

The Formula I compounds of the invention can be administered orformulated in combination with hormones. Examples of hormones include,but are not limited to, luteinizing hormone releasing hormone (LHRH),growth hormone (GH), growth hormone releasing hormone, ACTH,somatostatin, somatotropin, somatomedin, parathyroid hormone,hypothalamic releasing factors, insulin, glucagon, enkephalins,vasopressin, calcitonin, heparin, low molecular weight heparins,heparinoids, synthetic and natural opioids, insulin thyroid stimulatinghormones, and endorphins.

The Formula I compounds of the invention can be administered orformulated in combination with β-interferons which include, but are notlimited to, interferon β-1a, interferon β-1b.

The Formula I compounds of the invention can be administered orformulated in combination with α-interferons which include, but are notlimited to, interferon α-1, interferon α-2a (roferon), interferon α-2b,intron, Peg-Intron, Pegasys, consensus interferon (infergen) andalbuferon.

The Formula I compounds of the invention can be administered orformulated in combination with an absorption enhancer, particularlythose which target the lymphatic system, including, but not limited tosodium glycocholate; sodium caprate; N-lauryl-β-D-maltopyranoside; EDTA;mixed micelle; and those reported in Muranishi Crit. Rev. Ther. DrugCarrier Syst., 7-1-33, which is hereby incorporated by reference in itsentirety. Other known absorption enhancers can also be used. Thus, theinvention also encompasses a pharmaceutical composition comprising oneor more Formula I compounds of the invention and one or more absorptionenhancers.

The Formula I compounds of the invention can be administered orformulated in combination with an alkylating agent. Examples ofalkylating agents include, but are not limited to nitrogen mustards,ethylenimines, methylmelamines, alkyl sulfonates, nitrosoureas,triazenes, mechlorethamine, cyclophosphamide, ifosfamide, melphalan,chlorambucil, hexamethylmelaine, thiotepa, busulfan, carmustine,streptozocin, dacarbazine and temozolomide.

The compounds of the invention and the other therapeutics agent can actadditively or, more preferably, synergistically. In one embodiment, acomposition comprising a compound of the invention is administeredconcurrently with the administration of another therapeutic agent, whichcan be part of the same composition or in a different composition fromthat comprising the compounds of the invention. In another embodiment, acompound of the invention is administered prior to or subsequent toadministration of another therapeutic agent. In a separate embodiment, acompound of the invention is administered to a patient who has notpreviously undergone or is not currently undergoing treatment withanother therapeutic agent, particularly an antiviral agent.

In one embodiment, the methods of the invention comprise theadministration of one or more Formula I compounds of the inventionwithout an additional therapeutic agent.

Pharmaceutical Compositions and Dosage Forms

Pharmaceutical compositions and single unit dosage forms comprising aFormula I compound of the invention, or a pharmaceutically acceptablesalt, or hydrate thereof, are also encompassed by the invention.Individual dosage forms of the invention may be suitable for oral,mucosal (including sublingual, buccal, rectal, nasal, or vaginal),parenteral (including subcutaneous, intramuscular, bolus injection,intraarterial, or intravenous), transdermal, or topical administration.Pharmaceutical compositions and dosage forms of the invention typicallyalso comprise one or more pharmaceutically acceptable excipients.Sterile dosage forms are also contemplated.

In an alternative embodiment, pharmaceutical composition encompassed bythis embodiment includes a Formula I compound of the invention, or apharmaceutically acceptable salt, or hydrate thereof, and at least oneadditional therapeutic agent. Examples of additional therapeutic agentsinclude, but are not limited to, those listed above.

The composition, shape, and type of dosage forms of the invention willtypically vary depending on their use. For example, a dosage form usedin the acute treatment of a disease or a related disease may containlarger amounts of one or more of the active ingredients it comprisesthan a dosage form used in the chronic treatment of the same disease.Similarly, a parenteral dosage form may contain smaller amounts of oneor more of the active ingredients it comprises than an oral dosage formused to treat the same disease or disorder. These and other ways inwhich specific dosage forms encompassed by this invention will vary fromone another will be readily apparent to those skilled in the art. See,e.g., Remington's Pharmaceutical Sciences, 18th ed., Mack Publishing,Easton Pa. (1990). Examples of dosage forms include, but are not limitedto: tablets; caplets; capsules, such as soft elastic gelatin capsules;cachets; troches; lozenges; dispersions; suppositories; ointments;cataplasms (poultices); pastes; powders; dressings; creams; plasters;solutions; patches; aerosols (e.g., nasal sprays or inhalers); gels;liquid dosage forms suitable for oral or mucosal administration to apatient, including suspensions (e.g., aqueous or non-aqueous liquidsuspensions, oil-in-water emulsions, or a water-in-oil liquidemulsions), solutions, and elixirs; liquid dosage forms suitable forparenteral administration to a patient; and sterile solids (e.g.,crystalline or amorphous solids) that can be reconstituted to provideliquid dosage forms suitable for parenteral administration to a patient.

Typical pharmaceutical compositions and dosage forms comprise one ormore carriers, excipients or diluents. Suitable excipients are wellknown to those skilled in the art of pharmacy, and non-limiting examplesof suitable excipients are provided herein. Whether a particularexcipient is suitable for incorporation into a pharmaceuticalcomposition or dosage form depends on a variety of factors well known inthe art including, but not limited to, the way in which the dosage formwill be administered to a patient. For example, oral dosage forms suchas tablets may contain excipients not suited for use in parenteraldosage forms. The suitability of a particular excipient may also dependon the specific active ingredients in the dosage form.

This invention further encompasses anhydrous pharmaceutical compositionsand dosage forms comprising active ingredients, since water canfacilitate the degradation of some compounds. For example, the additionof water (e.g., 5%) is widely accepted in the pharmaceutical arts as ameans of simulating long-term storage in order to determinecharacteristics such as shelf-life or the stability of formulations overtime. See, e.g, Carstensen, Drug Stability: Principles & Practice, 2d.Ed., Marcel Dekker, NY, N.Y., 1995, pp. 379-80. In effect, water andheat accelerate the decomposition of some compounds. Thus, the effect ofwater on a formulation can be of great significance since moistureand/or humidity are commonly encountered during manufacture, handling,packaging, storage, shipment, and use of formulations.

Anhydrous pharmaceutical compositions and dosage forms of the inventioncan be prepared using anhydrous or low moisture containing ingredientsand low moisture or low humidity conditions.

An anhydrous pharmaceutical composition should be prepared and storedsuch that its anhydrous nature is maintained. Accordingly, anhydrouscompositions are preferably packaged using materials known to preventexposure to water such that they can be included in suitable formularykits. Examples of suitable packaging include, but are not limited to,hermetically sealed foils, plastics, unit dose containers (e.g., vials),blister packs, and strip packs.

The invention further encompasses pharmaceutical compositions and dosageforms that comprise one or more compounds that reduce the rate by whichan active ingredient will decompose. Such compounds, which are referredto herein as “stabilizers,” include, but are not limited to,antioxidants such as ascorbic acid, pH buffers, or salt buffers.

Like the amounts and types of excipients, the amounts and specific typesof active ingredients in a dosage form may differ depending on factorssuch as, but not limited to, the route by which it is to be administeredto patients. However, typical dosage forms of the invention compriseFormula I compounds of the invention, or a pharmaceutically acceptablesalt or hydrate thereof comprise 0.1 mg to 1500 mg per unit to providedoses of about 0.01 to 200 mg/kg per day.

Oral Dosage Forms

Pharmaceutical compositions of the invention that are suitable for oraladministration can be presented as discrete dosage forms, such as, butare not limited to, tablets (e.g., chewable tablets), caplets, capsules,and liquids (e.g., flavored syrups). Such dosage forms containpredetermined amounts of active ingredients, and may be prepared bymethods of pharmacy well known to those skilled in the art. Seegenerally, Remington's Pharmaceutical Sciences, 18th ed., MackPublishing, Easton Pa. (1990).

Typical oral dosage forms of the invention are prepared by combining theactive ingredient(s) in an intimate admixture with at least oneexcipient according to conventional pharmaceutical compoundingtechniques. Excipients can take a wide variety of forms depending on theform of preparation desired for administration. For example, excipientssuitable for use in oral liquid or aerosol dosage forms include, but arenot limited to, water, glycols, oils, alcohols, flavoring agents,preservatives, and coloring agents. Examples of excipients suitable foruse in solid oral dosage forms (e.g., powders, tablets, capsules, andcaplets) include, but are not limited to, starches, sugars,micro-crystalline cellulose, diluents, granulating agents, lubricants,binders, and disintegrating agents.

Because of their ease of administration, tablets and capsules representthe most advantageous oral dosage unit forms, in which case solidexcipients are employed. If desired, tablets can be coated by standardaqueous or nonaqueous techniques. Such dosage forms can be prepared byany of the methods of pharmacy. In general, pharmaceutical compositionsand dosage forms are prepared by uniformly and intimately admixing theactive ingredients with liquid carriers, finely divided solid carriers,or both, and then shaping the product into the desired presentation ifnecessary.

For example, a tablet can be prepared by compression or molding.Compressed tablets can be prepared by compressing in a suitable machinethe active ingredients in a free-flowing form such as powder orgranules, optionally mixed with an excipient. Molded tablets can be madeby molding in a suitable machine a mixture of the powdered compoundmoistened with an inert liquid diluent.

Examples of excipients that can be used in oral dosage forms of theinvention include, but are not limited to, binders, fillers,disintegrants, and lubricants. Binders suitable for use inpharmaceutical compositions and dosage forms include, but are notlimited to, corn starch, potato starch, or other starches, gelatin,natural and synthetic gums such as acacia, sodium alginate, alginicacid, other alginates, powdered tragacanth, guar gum, cellulose and itsderivatives (e.g., ethyl cellulose, cellulose acetate, carboxymethylcellulose calcium, sodium carboxymethyl cellulose), polyvinylpyrrolidone, methyl cellulose, pre-gelatinized starch, hydroxypropylmethyl cellulose, (e.g., Nos. 2208, 2906, 2910), microcrystallinecellulose, and mixtures thereof.

Examples of fillers suitable for use in the pharmaceutical compositionsand dosage forms disclosed herein include, but are not limited to, talc,calcium carbonate (e.g., granules or powder), microcrystallinecellulose, powdered cellulose, dextrates, kaolin, mannitol, silicicacid, sorbitol, starch, pre-gelatinized starch, and mixtures thereof.The binder or filler in pharmaceutical compositions of the invention istypically present in from about 50 to about 99 weight percent of thepharmaceutical composition or dosage form.

Suitable forms of microcrystalline cellulose include, but are notlimited to, the materials sold as AVICEL-PH-101, AVICEL-PH-103 AVICELRC-581, AVICEL-PH-105 (available from FMC Corporation, American ViscoseDivision, Avicel Sales, Marcus Hook, Pa.), and mixtures thereof. Aspecific binder is a mixture of microcrystalline cellulose and sodiumcarboxymethyl cellulose sold as AVICEL RC-581. Suitable anhydrous or lowmoisture excipients or additives include AVICEL-PH-103™ and Starch 1500LM.

Disintegrants are used in the compositions of the invention to providetablets that disintegrate when exposed to an aqueous environment.Tablets that contain too much disintegrant may disintegrate in storage,while those that contain too little may not disintegrate at a desiredrate or under the desired conditions. Thus, a sufficient amount ofdisintegrant that is neither too much nor too little to detrimentallyalter the release of the active ingredients should be used to form solidoral dosage forms of the invention. The amount of disintegrant usedvaries based upon the type of formulation, and is readily discernible tothose of ordinary skill in the art. Typical pharmaceutical compositionscomprise from about 0.5 to about 15 weight percent of disintegrant,specifically from about 1 to about 5 weight percent of disintegrant.

Disintegrants that can be used in pharmaceutical compositions and dosageforms of the invention include, but are not limited to, agar-agar,alginic acid, calcium carbonate, microcrystalline cellulose,croscarmellose sodium, crospovidone, polacrilin potassium, sodium starchglycolate, potato or tapioca starch, pre-gelatinized starch, otherstarches, clays, other algins, other celluloses, gums, and mixturesthereof.

Lubricants that can be used in pharmaceutical compositions and dosageforms of the invention include, but are not limited to, calciumstearate, magnesium stearate, mineral oil, light mineral oil, glycerin,sorbitol, mannitol, polyethylene glycol, other glycols, stearic acid,sodium lauryl sulfate, talc, hydrogenated vegetable oil (e.g., peanutoil, cottonseed oil, sunflower oil, sesame oil, olive oil, corn oil, andsoybean oil), zinc stearate, ethyl oleate, ethyl laureate, agar, andmixtures thereof. Additional lubricants include, for example, a syloidsilica gel (AEROSIL 200, manufactured by W.R. Grace Co. of Baltimore,Md.), a coagulated aerosol of synthetic silica (marketed by Degussa Co.of Plano, Tex.), CAB-O-SIL (a pyrogenic silicon dioxide product sold byCabot Co. of Boston, Mass.), and mixtures thereof. If used at all,lubricants are typically used in an amount of less than about 1 weightpercent of the pharmaceutical compositions or dosage forms into whichthey are incorporated.

Delayed Release Dosage Forms

Active ingredients of the invention can be administered by controlledrelease means or by delivery devices that are well known to those ofordinary skill in the art. Examples include, but are not limited to,those described in U.S. Pat. Nos. 3,845,770; 3,916,899; 3,536,809;3,598,123; and 4,008,719, 5,674,533, 5,059,595, 5,591,767, 5,120,548,5,073,543, 5,639,476, 5,354,556, and 5,733,566, each of which isincorporated herein by reference. Such dosage forms can be used toprovide slow or controlled-release of one or more active ingredientsusing, for example, hydropropylmethyl cellulose, other polymer matrices,gels, permeable membranes, osmotic systems, multilayer coatings,microparticles, liposomes, microspheres, or a combination thereof toprovide the desired release profile in varying proportions. Suitablecontrolled-release formulations known to those of ordinary skill in theart, including those described herein, can be readily selected for usewith the active ingredients of the invention. The invention thusencompasses single unit dosage forms suitable for oral administrationsuch as, but not limited to, tablets, capsules, gelcaps, and capletsthat are adapted for controlled-release.

All controlled-release pharmaceutical products have a common goal ofimproving drug therapy over that achieved by their non-controlledcounterparts. Ideally, the use of an optimally designedcontrolled-release preparation in medical treatment is characterized bya minimum of drug substance being employed to cure or control thecondition in a minimum amount of time. Advantages of controlled-releaseformulations include extended activity of the drug, reduced dosagefrequency, and increased patient compliance. In addition,controlled-release formulations can be used to affect the time of onsetof action or other characteristics, such as blood levels of the drug,and can thus affect the occurrence of side (e.g., adverse) effects.

Most controlled-release formulations are designed to initially releasean amount of drug (active ingredient) that promptly produces the desiredtherapeutic effect, and gradually and continually release of otheramounts of drug to maintain this level of therapeutic or prophylacticeffect over an extended period of time. In order to maintain thisconstant level of drug in the body, the drug must be released from thedosage form at a rate that will replace the amount of drug beingmetabolized and excreted from the body. Controlled-release of an activeingredient can be stimulated by various conditions including, but notlimited to, pH, temperature, enzymes, water, or other physiologicalconditions or compounds.

Parenteral Dosage Forms

Parenteral dosage forms can be administered to patients by variousroutes including, but not limited to, subcutaneous, intravenous(including bolus injection), intramuscular, and intraarterial. Becausetheir administration typically bypasses patients' natural defensesagainst contaminants, parenteral dosage forms are preferably sterile orcapable of being sterilized prior to administration to a patient.Examples of parenteral dosage forms include, but are not limited to,solutions ready for injection, dry and/or lyophylized products ready tobe dissolved or suspended in a pharmaceutically acceptable vehicle forinjection (reconstitutable powders), suspensions ready for injection,and emulsions.

Suitable vehicles that can be used to provide parenteral dosage forms ofthe invention are well known to those skilled in the art. Examplesinclude, but are not limited to: Water for Injection USP; aqueousvehicles such as, but not limited to, Sodium Chloride Injection,Ringer's Injection, Dextrose Injection, Dextrose and Sodium ChlorideInjection, and Lactated Ringer's Injection; water-miscible vehicles suchas, but not limited to, ethyl alcohol, polyethylene glycol, andpolypropylene glycol; and non-aqueous vehicles such as, but not limitedto, corn oil, cottonseed oil, peanut oil, sesame oil, ethyl oleate,isopropyl myristate, and benzyl benzoate.

Compounds that increase the solubility of one or more of the activeingredients disclosed herein can also be incorporated into theparenteral dosage forms of the invention.

Transdermal Dosage Forms

Transdermal dosage forms include “reservoir type” or “matrix type”patches, which can be applied to the skin and worn for a specific periodof time to permit the penetration of a desired amount of activeingredients.

Suitable excipients (e.g. carriers and diluents) and other materialsthat can be used to provide transdermal and topical dosage formsencompassed by this invention are well known to those skilled in thepharmaceutical arts, and depend on the particular tissue to which agiven pharmaceutical composition or dosage form will be applied. Withthat fact in mind, typical excipients include, but are not limited to,water, acetone, ethanol, ethylene glycol, propylene glycol,butane-1,3-diol, isopropyl myristate, isopropyl palmitate, mineral oil,and mixtures thereof.

Depending on the specific tissue to be treated, additional componentsmay be used prior to, in conjunction with, or subsequent to treatmentwith active ingredients of the invention. For example, penetrationenhancers can be used to assist in delivering the active ingredients tothe tissue. Suitable penetration enhancers include, but are not limitedto: acetone; various alcohols such as ethanol, oleyl, andtetrahydrofuryl; alkyl sulfoxides such as dimethyl sulfoxide; dimethylacetamide; dimethyl formamide; polyethylene glycol; pyrrolidones such aspolyvinylpyrrolidone; Kollidon grades (Povidone, Polyvidone); urea; andvarious water-soluble or insoluble sugar esters such as Tween 80(polysorbate 80) and Span 60 (sorbitan monostearate).

The pH of a pharmaceutical composition or dosage form, or of the tissueto which the pharmaceutical composition or dosage form is applied, mayalso be adjusted to improve delivery of one or more active ingredients.Similarly, the polarity of a solvent carrier, its ionic strength, ortonicity can be adjusted to improve delivery. Compounds such asstearates can also be added to pharmaceutical compositions or dosageforms to advantageously alter the hydrophilicity or lipophilicity of oneor more active ingredients so as to improve delivery. In this regard,stearates can serve as a lipid vehicle for the formulation, as anemulsifying agent or surfactant, and as a delivery-enhancing orpenetration-enhancing agent. Different salts, hydrates or solvates ofthe active ingredients can be used to further adjust the properties ofthe resulting composition.

Topical Dosage Forms

Topical dosage forms of the invention include, but are not limited to,creams, lotions, ointments, gels, solutions, emulsions, suspensions, orother forms known to one of skill in the art. See, e.g. Remington'sPharmaceutical Sciences, 18th eds., Mack Publishing, Easton Pa. (1990);and Introduction to Pharmaceutical Dosage Forms, 4th ed., Lea & Febiger,Philadelphia (1985).

Suitable excipients (e.g. carriers and diluents) and other materialsthat can be used to provide transdermal and topical dosage formsencompassed by this invention are well known to those skilled in thepharmaceutical arts, and depend on the particular tissue to which agiven pharmaceutical composition or dosage form will be applied. Withthat fact in mind, typical excipients include, but are not limited to,water, acetone, ethanol, ethylene glycol, propylene glycol,butane-1,3-diol, isopropyl myristate, isopropyl palmitate, mineral oil,and mixtures thereof.

Depending on the specific tissue to be treated, additional componentsmay be used prior to, in conjunction with, or subsequent to treatmentwith active ingredients of the invention. For example, penetrationenhancers can be used to assist in delivering the active ingredients tothe tissue. Suitable penetration enhancers include, but are not limitedto: acetone; various alcohols such as ethanol, oleyl, andtetrahydrofuryl; alkyl sulfoxides such as dimethyl sulfoxide; dimethylacetamide; dimethyl formamide; polyethylene glycol; pyrrolidones such aspolyvinylpyrrolidone; Kollidon grades (Povidone, Polyvidone); urea; andvarious water-soluble or insoluble sugar esters such as Tween 80(polysorbate 80) and Span 60 (sorbitan monostearate).

Mucosal Dosage Forms

Mucosal dosage forms of the invention include, but are not limited to,ophthalmic solutions, sprays and aerosols, or other forms known to oneof skill in the art. See, e.g., Remington's Pharmaceutical Sciences,18th eds., Mack Publishing, Easton Pa. (1990); and Introduction toPharmaceutical Dosage Forms, 4th ed., Lea & Febiger, Philadelphia(1985). Dosage forms suitable for treating mucosal tissues within theoral cavity can be formulated as mouthwashes or as oral gels. In oneembodiment, the aerosol comprises a carrier. In another embodiment, theaerosol is carrier free.

The Formula I compounds of the invention may also be administereddirectly to the lung by inhalation. For administration by inhalation, aFormula I compound can be conveniently delivered to the lung by a numberof different devices. For example, a Metered Dose Inhaler (“MDI”) whichutilizes canisters that contain a suitable low boiling propellant, e.g.,dichlorodifluoromethane, trichlorofluoromethane,dichlorotetrafluoroethane, carbon dioxide or other suitable gas can beused to deliver a Formula I compound directly to the lung. MDI devicesare available from a number of suppliers such as 3M Corporation,Aventis, Boehringer Ingleheim, Forest Laboratories, Glaxo-Wellcome,Schering Plough and Vectura.

Alternatively, a Dry Powder Inhaler (DPI) device can be used toadminister a Formula I compound to the lung (see, e.g., Raleigh et al.,Proc. Amer. Assoc. Cancer Research Annual Meeting, 1999, 40, 397, whichis herein incorporated by reference). DPI devices typically use amechanism such as a burst of gas to create a cloud of dry powder insidea container, which can then be inhaled by the patient. DPI devices arealso well known in the art and can be purchased from a number of vendorswhich include, for example, Fisons, Glaxo-Wellcome, Inhale TherapeuticSystems, ML Laboratories, Qdose and Vectura. A popular variation is themultiple dose DPI (“MDDPI”) system, which allows for the delivery ofmore than one therapeutic dose. MDDPI devices are available fromcompanies such as AstraZeneca, GlaxoWellcome, IVAX, Schering Plough,SkyePharma and Vectura. For example, capsules and cartridges of gelatinfor use in an inhaler or insufflator can be formulated containing apowder mix of the compound and a suitable powder base such as lactose orstarch for these systems.

Another type of device that can be used to deliver a Formula I compoundto the lung is a liquid spray device supplied, for example, by AradigmCorporation. Liquid spray systems use extremely small nozzle holes toaerosolize liquid drug formulations that can then be directly inhaledinto the lung.

In one embodiment, a nebulizer device is used to deliver a Formula Icompound to the lung. Nebulizers create aerosols from liquid drugformulations by using, for example, ultrasonic energy to form fineparticles that can be readily inhaled (See e.g., Verschoyle et al.,British J. Cancer, 1999, 80, Suppl 2, 96, which is herein incorporatedby reference). Examples of nebulizers include devices supplied bySheffield/Systemic Pulmonary Delivery Ltd. (See, Armer et al., U.S. Pat.No. 5,954,047; van der Linden et al., U.S. Pat. No. 5,950,619; van derLinden et al., U.S. Pat. No. 5,970,974, which are herein incorporated byreference), Aventis and Batelle Pulmonary Therapeutics.

In one embodiment, an electrohydrodynamic (“EHD”) aerosol device is usedto deliver Formula I compounds to the lung. EHD aerosol devices useelectrical energy to aerosolize liquid drug solutions or suspensions(see, e.g., Noakes et al., U.S. Pat. No. 4,765,539; Coffee, U.S. Pat.No. 4,962,885; Coffee, PCT Application, WO 94/12285; Coffee, PCTApplication, WO 94/14543; Coffee, PCT Application, WO 95/26234, Coffee,PCT Application, WO 95/26235, Coffee, PCT Application, WO 95/32807,which are herein incorporated by reference). The electrochemicalproperties of the Formula I compounds formulation may be importantparameters to optimize when delivering this drug to the lung with an EHDaerosol device and such optimization is routinely performed by one ofskill in the art. EHD aerosol devices may more efficiently deliverydrugs to the lung than existing pulmonary delivery technologies. Othermethods of intra-pulmonary delivery of Formula I compounds will be knownto the skilled artisan and are within the scope of the invention.

Liquid drug formulations suitable for use with nebulizers and liquidspray devices and EHD aerosol devices will typically include a Formula Icompound with a pharmaceutically acceptable carrier. Preferably, thepharmaceutically acceptable carrier is a liquid such as alcohol, water,polyethylene glycol or a perfluorocarbon. Optionally, another materialmay be added to alter the aerosol properties of the solution orsuspension of the Formula I compound. Preferably, this material isliquid such as an alcohol, glycol, polyglycol or a fatty acid. Othermethods of formulating liquid drug solutions or suspension suitable foruse in aerosol devices are known to those of skill in the art (see,e.g., Biesalski, U.S. Pat. Nos. 5,112,598; Biesalski, 5,556,611, whichare herein incorporated by reference) A Formula I compound can also beformulated in rectal or vaginal compositions such as suppositories orretention enemas, e.g. containing conventional suppository bases such ascocoa butter or other glycerides.

In addition to the formulations described previously, a Formula Icompound can also be formulated as a depot preparation. Such long actingformulations can be administered by implantation (for examplesubcutaneously or intramuscularly) or by intramuscular injection. Thus,for example, the compounds can be formulated with suitable polymeric orhydrophobic materials (for example, as an emulsion in an acceptable oil)or ion exchange resins, or as sparingly soluble derivatives, forexample, as a sparingly soluble salt.

Alternatively, other pharmaceutical delivery systems can be employed.Liposomes and emulsions are well known examples of delivery vehiclesthat can be used to deliver Formula I compounds. Certain organicsolvents such as dimethylsulfoxide can also be employed, althoughusually at the cost of greater toxicity. A Formula I compound can alsobe delivered in a controlled release system. In one embodiment, a pumpcan be used (Sefton, CRC Crit. Ref Biomed Eng., 1987, 14, 201; Buchwaldet al., Surgery, 1980, 88, 507; Saudek et al., N. Engl. J. Med., 1989,321, 574). In another embodiment, polymeric materials can be used (seeMedical Applications of Controlled Release, Langer and Wise (eds.), CRCPres., Boca Raton, Fla. (1974); Controlled Drug Bioavailability, DrugProduct Design and Performance, Smolen and Ball (eds.), Wiley, New York(1984); Ranger and Peppas, J. Macromol. Sci. Rev. Macromol. Chem., 1983,23, 61; see also Levy et al., Science, 1985, 228, 190; During et al.,Ann. Neurol., 1989, 25, 351; Howard et al., J. Neurosurg., 71, 105(1989). In yet another embodiment, a controlled-release system can beplaced in proximity of the target of the compounds of the invention,e.g., the lung, thus requiring only a fraction of the systemic dose(see, e.g., Goodson, in Medical Applications of Controlled Release,supra, vol. 2, pp. 115 (1984)). Other controlled-release system can beused (see, e.g., Langer, Science, 1990, 249, 1527).

Suitable excipients (e.g., carriers and diluents) and other materialsthat can be used to provide mucosal dosage forms encompassed by thisinvention are well known to those skilled in the pharmaceutical arts,and depend on the particular site or method which a given pharmaceuticalcomposition or dosage form will be administered. With that fact in mind,typical excipients include, but are not limited to, water, ethanol,ethylene glycol, propylene glycol, butane-1,3-diol, isopropyl myristate,isopropyl palmitate, mineral oil, and mixtures thereof, which arenon-toxic and pharmaceutically acceptable. Examples of such additionalingredients are well known in the art. See, e.g, Remington'sPharmaceutical Sciences, 18th eds., Mack Publishing, Easton Pa. (1990).

The pH of a pharmaceutical composition or dosage form, or of the tissueto which the pharmaceutical composition or dosage form is applied, canalso be adjusted to improve delivery of one or more active ingredients.Similarly, the polarity of a solvent carrier, its ionic strength, ortonicity can be adjusted to improve delivery. Compounds such asstearates can also be added to pharmaceutical compositions or dosageforms to advantageously alter the hydrophilicity or lipophilicity of oneor more active ingredients so as to improve delivery. In this regard,stearates can serve as a lipid vehicle for the formulation, as anemulsifying agent or surfactant, and as a delivery-enhancing orpenetration-enhancing agent. Different salts, hydrates or solvates ofthe active ingredients can be used to further adjust the properties ofthe resulting composition.

Kits

The invention provides a pharmaceutical pack or kit comprising one ormore containers comprising a Formula I compound useful for the treatmentor prevention of a Hepatitis C virus infection. In other embodiments,the invention provides a pharmaceutical pack or kit comprising one ormore containers comprising a Formula I compound useful for the treatmentor prevention of a Hepatitis C virus infection and one or morecontainers comprising an additional therapeutic agent, including but notlimited to those listed above, in particular an antiviral agent, aninterferon, an agent which inhibits viral enzymes, or an agent whichinhibits viral replication, preferably the additional therapeutic agentis HCV specific or demonstrates anti-HCV activity.

The invention also provides a pharmaceutical pack or kit comprising oneor more containers comprising one or more of the ingredients of thepharmaceutical compositions of the invention. Optionally associated withsuch container(s) can be a notice in the form prescribed by agovernmental agency regulating the manufacture, use or sale ofpharmaceuticals or biological products, which notice reflects approvalby the agency of manufacture, use or sale for human administration.

The inventive agents may be prepared using the reaction routes andsynthesis schemes as described below, employing the general techniquesknown in the art using starting materials that are readily available.The synthesis of non-exemplified compounds according to the inventionmay be successfully performed by modifications apparent to those skilledin the art, e.g., by appropriately protecting interfering groups, bychanging to other suitable reagents known in the art, or by makingroutine modifications of reaction conditions. Alternatively, otherreactions disclosed herein or generally known in the art will berecognized as having applicability for preparing other compounds of theinvention.

Preparation of Compounds

In the synthetic schemes described below, unless otherwise indicated alltemperatures are set forth in degrees Celsius and all parts andpercentages are by weight.

Reagents were purchased from commercial suppliers such as AldrichChemical Company or Lancaster Synthesis Ltd. and were used withoutfurther purification unless otherwise indicated. All solvents werepurchased from commercial suppliers such as Aldrich, EMD Chemicals orFisher and used as received.

The reactions set forth below were done generally under a positivepressure of argon or nitrogen at an ambient temperature (unlessotherwise stated) in anhydrous solvents, and the reaction flasks werefitted with rubber septa for the introduction of substrates and reagentsvia syringe. Glassware was oven dried and/or heat dried.

The reactions were assayed by TLC and/or analyzed by LC-MS andterminated as judged by the consumption of starting material. Analyticalthin layer chromatography (TLC) was performed on glass-plates precoatedwith silica gel 60 F₂₅₄ 0.25 mm plates (EMD Chemicals), and visualizedwith UV light (254 nm) and/or iodine on silica gel and/or heating withTLC stains such as ethanolic phosphomolybdic acid, ninhydrin solution,potassium permanganate solution or ceric sulfate solution. Preparativethin layer chromatography (prepTLC) was performed on glass-platesprecoated with silica gel 60 F₂₅₄ 0.5 mm plates (20×20 cm, from ThomsonInstrument Company) and visualized with UV light (254 nm).

Work-ups were typically done by doubling the reaction volume with thereaction solvent or extraction solvent and then washing with theindicated aqueous solutions using 25% by volume of the extraction volumeunless otherwise indicated. Product solutions were dried over anhydrousNa₂SO₄ and/or MgSO₄ prior to filtration and evaporation of the solventsunder reduced pressure on a rotary evaporator and noted as solventsremoved in vacuo. Column chromatography was completed under positivepressure using Merck silica gel 60, 230-400 mesh or 50-200 mesh neutralalumina, ISCO Flash-chromatography using prepacked RediSep silica gelcolumns, or Analogix flash column chromatography using prepackedSuperFlash silica gel columns. Hydrogenolysis was done at the pressureindicated in the examples or at ambient pressure.

¹H-NMR spectra and ¹³C-NMR were recorded on a Varian Mercury-VX400instrument operating at 400 MHz. NMR spectra were obtained as CDCl₃solutions (reported in ppm), using chloroform as the reference standard(7.27 ppm for the proton and 77.00 ppm for carbon), CD₃OD (3.4 and 4.8ppm for the protons and 49.3 ppm for carbon), DMSO-d₆ (2.49 ppm forproton), or internally tetramethylsilane (0.00 ppm) when appropriate.Other NMR solvents were used as needed. When peak multiplicities arereported, the following abbreviations are used: s (singlet), d(doublet), t (triplet), q (quartet), m (multiplet), br (broadened), bs(broad singlet), dd (doublet of doublets), dt (doublet of triplets).Coupling constants, when given, are reported in Hertz (Hz).

Infrared (IR) spectra were recorded on an ATR FT-IR Spectrometer as neatoils or solids, and when given are reported in wave numbers (cm⁻¹). Massspectra reported are (+)-ES or APCI (+) LC/MS conducted by theAnalytical Chemistry Department of Anadys Pharmaceuticals, Inc.Elemental analyses were conducted by the Atlantic Microlab, Inc. inNorcross, Ga. or by NuMega Resonance Labs, Inc. in San Diego, Calif.Melting points (mp) were determined on an open capillary apparatus, andare uncorrected.

The described synthetic pathways and experimental procedures may utilizemany common chemical abbreviations, 2,2-DMP (2,2-dimethoxypropane), Ac(acetyl), ACN (acetonitrile), Aliquat® 336 (trioctylmethylammoniumchloride), Bn (benzyl), BnOH (benzyl alcohol), Boc(tert-butoxycarbonyl), Boc₂O (di-tert-butyl dicarbonate), Bz (benzoyl),CSI (chlorosulfonyl isocyanate), DAST (diethylaminosulfur trifluoride),DBU (1,8-diazabicyclo[5,4,0]undec-7-ene), DCC(N,N′-dicyclohexylcarbodiimide), DCE (1,2-dichloroethane), DCM(dichloromethane), DEAD (diethylazodicarboxylate), DIEA(diisopropylethylamine), DMA (N,N-dimethylacetamide), DMAP(4-(N,N-dimethylamino)pyridine), DMF (N,N-dimethylformamide), DMSO(dimethyl sulfoxide), EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimidehydrochloride), Et (ethyl), EtOAc (ethyl acetate), EtOH (ethanol), Et₂O(diethyl ether), HATU(O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate), HBTU(O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate),HF (hydrogen fluoride), HOAc (acetic acid), HOBT (1-hydroxybenzotriazolehydrate), HPLC (high pressure liquid chromatography), iPrOH (isopropylalcohol), IPA (isopropyl alcohol), KHMDS (potassiumbis(trimethylsilyl)amide), KN(TMS)₂ (potassiumbis(trimethylsilyl)amide), KO^(t)Bu (potassium tert-butoxide), KOH(potassium hydroxide), LDA (lithium diisopropylamine), MCPBA(3-chloroperbenzoic acid), Me (methyl), MeCN (acetonitrile), MeOH(methanol), MTBE (methyl tert-butyl ether), NaCNBH₃ (sodiumcyanoborohydride), NaH (sodium hydride), NaN(TMS)₂ (sodiumbis(trimethylsilyl)amide), NaOAc (sodium acetate), NaOEt (sodiumethoxide), NIS (N-iodosuccinimide), Phe (phenylalanine), PPTS(pyridinium p-toluenesulfonate), PS (polymer supported), Py (pyridine),pyBOP (benzotriazol-1-yloxy)tripyrrolidinophosphoniumhexafluorophosphate), TEA (triethylamine), TFA (trifluoroacetic acid),TFAA (trifluoroacetic anhydride), THF (tetrahydrofuran), TLC (thin layerchromatography), Tol (toluoyl), Val (valine), and the like.

Scheme 1 provides a general procedure that was used to prepare3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I.

The cyclic anhydride intermediate, which can be obtained as describedbelow, can be condensed with a dialkylmalonate in the presence of astrong base, such as sodium hydride, to yield the shown ester. The estercan be fused together with an ortho-amino sulfonamide compound to formthe amide, which can be cyclized in the presence of a base (e.g., aq.KOH) to give the desired3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds.

Scheme 2 provides a general procedure that can be used to prepare thecyclic anhydride intermediates.

Commercially available pyrrole-2-carboxylic acid esters (alternatively,the commercially available acid can be protected as a suitable esterusing standard methods for ester formation) can be N-aminated usingmonochloroamine to yield the hydrazine intermediates. These entities canbe N-alkylated by reacting them with aldehydes or ketones, where R^(x)and R^(w) are C₁-C₅ alkyl, C₃-C₈ cycloalkyl, —C₁-C₅ alkylene(C₃-C₈cycloalkyl), —C₁-C₅ alkylene(aryl), —C₁-C₅ alkylene(heterocyclyl), aryl,or heterocyclyl, or R^(w) can combine with R^(x) to form a 3- to8-membered ring, and a reducing agent, such as sodium cyanoborohydride.Deprotection of the esters followed by cyclization using phosgene orphosgene equivalents gives the desired cyclic anhydride intermediates.

Scheme 3 provides a procedure that was used to prepare the4-(3-methyl-butyl)-6-oxa-3a,4-diaza-indene-5,7-dione intermediate.

Pyrrole-2-carboxylic acid can be protected as an ester (e.g., allylester) using standard methods for ester formation. The ring nitrogen canbe N-aminated using monochloroamine to yield the hydrazine intermediate,which can be N-alkylated with an aldehyde using know methods ofreductive amination. Deprotection of the ester followed by cyclizationusing phosgene or phosgene equivalents can be used to give the desired4-(3-methyl-butyl)-6-oxa-3a,4-diaza-indene-5,7-dione intermediate.

Schemes 4(a) and 4(b) provide general procedures that were used toprepare the 2-amino-5-methanesulfonylamino-benzenesulfonamideintermediate.

Commercially available 4-nitroaniline can be treated with sulfonylchlorides, e.g., methanesulfonyl chloride, to obtain the correspondingsulfonamides. Reduction of the nitro group using standard conditionsaffords the corresponding anilines, which can be treated withchlorosulfonyl isocyanate followed by aluminum chloride to give thecorresponding1,1-dioxo-1,4-dihydro-2H-1λ⁶-benzo[1,2,4]thiadiazin-3-ones. Opening ofthe cyclic ureas with a strong acid (e.g., hydrochloric acid) gives thedesired 2-amino-5-sulfonylamino-benzenesulfonamide intermediates.

In a preferred route, commercially available 4-nitroaniline can betreated with sulfonyl chlorides, e.g., methanesulfonyl chloride, toobtain the corresponding sulfonamides. Reduction of the nitro groupusing standard conditions affords the corresponding anilines, which canbe treated with chlorosulfonyl isocyanate followed by aluminum chlorideto give the corresponding1,1-dioxo-1,4-dihydro-2H-1λ⁶-benzo[1,2,4]thiadiazin-3-ones. Opening ofthe cyclic ureas with a strong acid (e.g., sulfuric acid) gives thedesired 2-amino-5-sulfonylamino-benzenesulfonamide intermediates alongwith some of the hydrolyzed 2,5-diaminobenzenesulfonamide, which can beconverted back by treatment with sulfonyl chlorides, e.g.,methanesulfonyl chloride, to obtain the desired2-amino-5-sulfonylamino-benzenesulfonamide intermediates.

Scheme 5 provides a procedure that can be used to prepare the2-amino-5-methoxy-benzenesulfonamide intermediate.

Commercially available 4-methoxyaniline can be treated withchlorosulfonyl isocyanate followed by aluminum chloride to give thecorresponding7-methoxy-1,1-dioxo-1,4-dihydro-2H-1λ⁶-benzo[1,2,4]thiadiazin-3-one.Opening of the cyclic urea with a strong acid (e.g., sulfuric acid)gives the desired 2-amino-5-methoxy-benzenesulfonamide intermediate.

Scheme 6 provides a procedure that can be used to prepare the2-amino-5-iodo-benzenesulfonamide intermediate.

Commercially available 2-amino-benzensulfonamide can be treated withN-iodosuccinimide to give the desired 2-amino-5-iodo-benzenesulfonamideintermediate.

Scheme 7 provides an alternative general procedure that was used toprepare3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I.

The 1-substituted4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylic acidester intermediates can be fused together neat or in a suitable solvent(e.g., pyridine) with optionally substituted ortho-amino sulfonamidecompounds to form the corresponding amides. The amide intermediates canbe cyclized (without prior isolation) in the presence of a base (e.g.,DBU) to give the desired3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds.

Scheme 8 provides a general procedure that can be used to prepare1-substituted6-fluoro-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester intermediates.

Commercially available 4-oxo-pyrrolidine-1,2-dicarboxylic acid1-tert-butyl ester 2-methyl ester can be treated with a fluorinatingagent, such as DAST, to afford the corresponding difluoro intermediates.Hydrolysis of the ester gives the acid, which can then be transformedinto a suitable ester (such as an allyl ester) using standardconditions. Removal of the protecting group under standard conditionsgives the free amine. Subsequent oxidation with an oxidizing agent(e.g., manganese dioxide) leads to the corresponding pyrroleintermediate. N-Amination with monochloramine affords the hydrazineintermediate, which can be N-alkylated by treatment with aldehydes orketones, where R^(x) and R^(w) are C₁-C₅ alkyl, C₃-C₈ cycloalkyl, —C₁-C₅alkylene(C₃-C₈ cycloalkyl), —C₁-C₅ alkylene(aryl), —C₁-C₅alkylene(heterocyclyl), aryl, or heterocyclyl, or R^(w) can combine withR^(x) to form a 3- to 8-membered ring, and a reducing agent, such assodium cyanoborohydride. Acylation of the nitrogen with a malonylchlorides (e.g., methyl malonyl chloride) gives the correspondinghydrazides, which can be cyclized in the presence of a base (e.g.,sodium ethoxide) to give the desired 1-substituted6-fluoro-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester intermediates.

Scheme 9 provides a general procedure that can be used to prepare1-substituted6-cyano-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester intermediates.

A 1H-pyrrole-2-carboxylic acid ester, such as a methyl ester, can betreated with chlorosulfonyl isocyanate (CSI) followed byN,N-dimethylformamide to introduce the cyano moiety. N-Amination withmonochloramine affords the hydrazine intermediates, which can beN-alkylated by treatment with aldehydes or ketones, where R^(x) andR^(w) are C₁-C₅ alkyl, C₃-C₈ cycloalkyl, —C₁-C₅ alkylene(C₃-C₈cycloalkyl), —C₁-C₅ alkylene(aryl), —C₁-C₅ alkylene(heterocyclyl), aryl,or heterocyclyl, or R^(w) can combine with R^(x) to form a 3- to8-membered ring, and a reducing agent, such as sodium cyanoborohydride.Acylation of the nitrogen with a malonyl chloride monoester (such asmethyl malonyl chloride) gives the corresponding hydrazides, which canbe cyclized in the presence of a base (e.g., sodium ethoxide) to givethe desired 1-substituted6-cyano-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester intermediates.

Scheme 10 provides an alternative general procedure that was used toprepare3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I

The 1-substituted-1-amino-1H-pyrrole-2-carboxylic acid esters (e.g.,methyl esters), which can be prepared as described in schemes 2, 3, 8,and 9, can be coupled with acid intermediates using standard peptidecoupling conditions, such as DCC, to afford the corresponding amideintermediates. Treatment of these entities with a base (e.g., sodiumethoxide) gives the desired3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I.

Scheme II provides a general procedure that can be used to prepare7-substituted-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl-aceticacid intermediates.

Commercially available 2-chloro-5-nitro-benzenesulfonic acid can betreated with thionyl chloride to give the sulfonylchloride, which can befurther treated with ammonia to afford the sulfonamide intermediate. Thechloride can be displaced with ammonia by treatment with ammoniumhydroxide and ammonium carbonate in the presence of copper (II) sulfate.Reduction of the nitro group under standard hydrogenation conditionsaffords the aniline intermediate, which can be treated with a sulfonylchloride, such as methylsulfonyl chloride, to yield the correspondingsulfonamide. Acylation of the 2-amino moiety with malonyl chlorides,e.g., ethyl 3-chloro-3-oxo-propionate, gives the corresponding amide,which can simultaneously be cyclized to the thiadiazine-dioxide andhydrolyzed to the desired acid intermediate.

Scheme 12 provides an alternative procedure that can be used to preparethe 2-chloro-5-nitro-benzenesulfonamide intermediate.

Commercially available 1-chloro-4-nitro-benzene can be reacted withchlorosulfonic acid to afford the corresponding sulfonylchloride.Treatment with a saturated solution of ammonia in methanol affords thedesired the 2-chloro-5-nitro-benzenesulfonamide intermediate.

Scheme 13 provides an alternative procedure that can be used to preparethe 2,5-diamino-benzenesulfonamide intermediate.

The 2-chloro-5-nitro-benzenesulfonamide intermediate (prepared asdescribed in schemes 11 and 12) can be treated with a benzylic amine,such as benzyl amine, to displace the chloro moiety. Hydrogenation understandard conditions can be used to remove the benzylic group and toreduce the nitro group at the same time to afford the desired2,5-diamino-benzenesulfonamide intermediate.

Scheme 14 provides an alternative procedure that can be used to preparethe 2-amino-5-nitro-benzenesulfonamide intermediate.

The commercially available sodium salt of2-amino-5-nitro-benzenesulfonic acid can be converted to thecorresponding sulfonyl chloride with phosphoryl chloride in the presenceof a suitable co-solvent, such as sulfolane. Treatment with ammonia,e.g., ammonia solution in methanol or ammonia gas, affords the desired2-amino-5-nitro-benzenesulfonamide intermediate.

Scheme 15 provides an alternative procedure that can be used to preparethe 2-amino-5-nitro-benzenesulfonamide intermediate.

Commercially available 2-amino-5-nitro-benzenesulfonic acid can beconverted to the corresponding sulfonyl chloride with phosphorylchloride in the presence of a suitable co-solvent, such as sulfolane.Treatment with ammonia, e.g., aqueous ammonium hydroxide solution orammonia gas, affords the desired 2-amino-5-nitro-benzenesulfonamideintermediate.

Scheme 16 provides an alternative procedure that can be used to preparethe N-(4-methanesulfonylamino-2-sulfamoyl-phenyl)-malonamic acid ethylester intermediate.

2-Amino-5-methanesulfonylamino-benzenesulfonamide (prepared as describedin schemes 4 and 12) can be treated with a dialkyl malonate, such asdiethyl malonate, to afford the desiredN-(4-methanesulfonylamino-2-sulfamoyl-phenyl)-malonamic acid ethyl esterintermediate.

Scheme 17 provides a general procedure that can be used to prepare the(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid intermediate.

Acylation of 2-amino-5-iodo-benzenesulfonamide with a malonyl halidemonoester, such as ethyl 3-chloro-3-oxo-propionate, or with a dialkylmalonate, such as diethyl malonate, affords the corresponding amide,which can simultaneously be cyclized to the thiadiazine-dioxide andhydrolyzed to the desired acid intermediate.

Scheme 18 provides a general procedure that can be used to prepare the3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I from the corresponding iodo precursors.

Optionally substituted4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-onescan be treated with substituted sulfonamides in a copper-mediateddisplacement reaction to afford the desired3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I.

Scheme 19 provides a general procedure that can be used to prepare the3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I from the corresponding iodo precursors.

Optionally substituted4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-onescan be treated with stannanes, such as the unsaturated cyclic sulfoneshown above, in a Stille-type palladium-catalyzed reaction to afford theunsaturated intermediates shown. Reduction of the alkene using standardhydrogenation conditions affords the desired3-(1,1-dioxobenzo[1,2,4]thiadiazine)-pyrrolo[1,2-b]pyridazin-2-onecompounds of Formula I.

Scheme 20 provides a general procedure that can be used to prepare3-(1,1-dioxobenzo[1,4]thiazin)-pyrrolo[1,2-b]pyridazin-2-one compoundsof Formula I.

The cyclic anhydride and(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid ethyl ester intermediate can be condensed in the presence of a base(e.g., sodium hydride) to yield the desired3-(1,1-dioxobenzo[1,4]thiazin)-pyrrolo[1,2-b]pyridazin-2-one compound.

Scheme 21 provides a procedure that can be used to prepare the(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid ethyl ester intermediate.

Commercially available 6-nitrobenzothiazole can be treated withhydrazine to obtain the 2-amino-5-nitro-benzenethiol, which cansubsequently be reacted with chloroacetoacetate to give the(7-nitro-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethyl ester. Reductionof the nitro group to the amino group can be accomplished by reactionwith tin (II) chloride. Subsequent reaction with methansulfonyl chloridecan be used to obtain the corresponding sulfonamide. Protection of bothnitrogens with a suitable protecting group such as a Boc group can beachieved by using standard methods for protecting amino groups. Thesulfide can be oxidized using a suitable oxidizing reagent (e.g., MCPBA)to give the sulfone. Finally, deprotection of the amino groups usingtrifluoroacetic acid can be used to afford the desired(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid ethyl ester intermediate.

Scheme 22 provides a general procedure that can be used to prepare7-substituted-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl-aceticacid intermediates.

Hydrolysis of the7-substituted-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl-aceticacid ester can be accomplished using standard conditions (e.g., lithiumhydroxide) to afford the desired(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid intermediate.

Scheme 23 provides a general procedure that can be used to prepare7-(N-methyl)-substituted-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl-aceticacid intermediate.

Commercially available 6-aminobenzothiazole can be treated with asulfonyl chloride, such as methanesulfonyl chloride, to obtain thecorresponding sulfonamides. Reaction with methyl iodide, in the presenceof a base, gives the corresponding N-methyl sulfonamide. Reaction withhydrazine hydrate and subsequent treatment with methylchloroacetoacetate affords the corresponding4H-benzo[1,4]thiazin-3-yl)-acetic acid methyl ester. Protection of thering nitrogen with a suitable protecting group such as a Boc group canbe achieved by using standard methods for protecting amino groups. Thesulfide can be oxidized using a suitable oxidizing reagent (e.g., MCPBA)to give the sulfone. Finally, hydrolysis of the ester affords thedesired[7-(methanesulfonyl-methyl-amino)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl]-aceticacid intermediate.

EXAMPLE 13-(1,1-Dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-4-hydroxy-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one

a) 1H-Pyrrole-2-carboxylic acid allyl ester

To a solution of 1H-pyrrole-2-carboxylic acid (1.5 g, 14 mmol) inN,N-dimethylformamide (50 mL) at 25° C. was added cesium carbonate (4.8g, 14.7 mmol) and allyl bromide (1.34 mL, 15.4 mmol) and stirred for 16h. The reaction mixture was treated with saturated aqueous ammoniumchloride solution and diethyl ether (20 mL). The layers were separatedand the aqueous layers were extracted with diethyl ether (3×100 mL). Thecombined organic layers were dried over magnesium sulfate, filtered andconcentrated in vacuo to afford the crude desired product,1H-pyrrole-2-carboxylic acid allyl ester (1.6 g, 10.6 mmol, 76% yield)as a yellow oil, which was used in the next step without furtherpurification. ¹H NMR (400 MHz, CDCl₃) δ 4.77 (1H, m), 5.35 (1H, dd,J₁=10.4 Hz, J₂=1.2 Hz), 5.39 (1H, dd, J₁=16.8 Hz, J₂=1.6 Hz), 6.26 (1H,m), 5.96 (1H, m), 6.94 (2H, m), 9.2 (1H, bs).

b) 1-Amino-1H-pyrrole-2-carboxylic acid allyl ester

To a solution of 1H-pyrrole-2-carboxylic acid allyl ester (Example 1a,0.75 g, 4.96 mmol) in N,N-dimethylformamide (20 mL) at 25° C. was addedsodium hydride (0.316 g, 7.29 mmol) and stirred for 1 h. A solution ofmonochloroamine (36 mL, 7.19 mmol) in diethyl ether (0.2 M) was addedand stirred for 1 h and then treated with saturated aqueous sodiumbicarbonate solution (50 mL) and water (25 mL). The layers wereseparated and the aqueous layer was extracted with diethyl ether (3×50mL). The combined organic layers were dried over magnesium sulfate,filtered and concentrated in vacuo to afford the crude desired product,1-amino-1H-pyrrole-2-carboxylic acid allyl ester (0.90 g) as a yellowoil, which was used in the next step without further purification. ¹HNMR (400 MHz, CDCl₃) δ 4.75 (2H, m), 5.28 (1H, dd, J₁=10.0 Hz, J₂=1.2Hz), 5.40 (1H, dd, J₁=17.2 Hz, J₂=1.6 Hz), 6.03-5.90 (2H, m), 6.87 (1H,dd, J₁=4.0 Hz, J₂=1.6 Hz), 6.97 (1H, t, J=2.0 Hz).

Alternatively, 1-amino-1H-pyrrole-2-carboxylic acid allyl ester can beprepared as follows:

1H-Pyrrole-2-carboxylic acid allyl ester (Example 1a, 11.73 g, 78.12mmol) was dissolved in in methyl tert-butyl ether (150 mL) and asolution of sodium hydroxide (37 g, 925 mmol) in water (150 mL) wasadded. Solid ammonium chloride (25.1 g, 469 mmol),trioctylmethylammonium chloride (“Aliquat® 336”, 1 mL) and 28% aqueousammonium hydroxide solution (50 mL) were added to the biphasic mixture.Under vigorous stirring, a 6.15% aqueous bleach solution (“Chlorox”, 250mL) was slowly added over a period of 45 min via addition funnel uponwhich the color of the solution turned orange. After stirring for 1.5 hat 25° C., mixture was poured into methyl tert-butyl ether (150 mL) andthe layers were separated. The organic layer was washed with a solutionof sodium thiosulfate (10 g) in water (200 mL) and the organic layer wasdried over sodium sulfate and filtered. The solvent was removed in vacuoto afford the desired product, 1-amino-1H-pyrrole-2-carboxylic acidallyl ester (8.03 g, 48.32 mmol, 62% yield) as a brown oil.

c) 1-(3-Methyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester

To a solution of 1-amino-1H-pyrrole-2-carboxylic acid allyl ester(Example 1b, 0.88 g, 5.3 mmol) in methanol (12 mL) was added isovalerylaldehyde (0.74 mL, 6.9 mmol) and 1 drop 10% aqueous hydrochloric acid.The reaction mixture was stirred at 25° C. for 20 min, after whichsodium cyanoborohydride (0.201 g, 3.2 mmol) was added and the resultingyellow solution was heated at reflux for 16 h. The reaction was quenchedslowly with 10% aqueous hydrochloric acid and concentrated in vacuo. Thecrude slurry was redissolved in diethyl ether. The layers were separatedand the aqueous layer was extracted with diethyl ether. The combinedorganic layers were dried over magnesium sulfate, filtered andconcentrated in vacuo. The crude product was purified by columnchromatography (Merck silica gel 60, 40-63 μm, ethyl acetate/hexane,20-40%) to afford the desired product,1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester (0.70g, 2.96 mmol, 60% yield) as a yellow oil. ¹H NMR (400 MHz, CDCl₃) δ 0.92(6H, d, J=6.8 Hz), 1.42 (2H, q, J₁=14.4 Hz, J₂=7.2 Hz), 1.68 (1H, m),3.03 (2H, t, J=7.2 Hz), 4.76 (2H, d, J=5.6 Hz), 5.28 (1H, d, J=9.6 Hz),5.40 (1H, d, J=17.2 Hz), 6.01-6.04 (2H, m), 6.89-6.90 (1H, m), 6.96-6.97(1H, m).

d) 1-(3-Methyl-butylamino)-1H-pyrrole-2-carboxylic acid

To a solution of 1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acidallyl ester (Example 1c, 2.8 g, 16 mmol) in dichloromethane (70 mL) wasadded O-benzylhydroxylamine hydrochloride (2.56 g, 16 mmol).Tetrakis(triphenylphosphine)palladium(0) (3.6 g, 3.2 mmol) was added andthe reaction mixture was heated at reflux for 16 h. The crude mixturewas allowed to cool to 25° C. The solvent was removed in vacuo andredissolved in ethyl acetate (150 mL) and then washed with 10% aqueoushydrochloric acid solution (3×50 mL) and water (50 mL). The organiclayer was dried over magnesium sulfate, filtered and concentrated invacuo. The crude product was purified by column chromatography (Mercksilica gel 60, 40-63 μm, ethyl acetate/hexane, 20-60%) to afford thedesired product, 1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid(2.5 g, 13 mmol, 82% yield) as a yellow oil. ¹H NMR (400 MHz, CDCl₃) δ0.94 (6H, d, J=6.4 Hz), 1.41-1.47 (2H, q, J₁=15.2 Hz, J₂=6.8 Hz), 1.68(1H, m), 6.18 (1H, dd, J₁=4.0 Hz, J₂=2.8 Hz), 6.98-7.02 (2H, m).

(e) 4-(3-Methyl-butyl)-6-oxa-3a,4-diaza-indene-5,7-dione

To a solution of 1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid(Example 1d, 0.25 g, 1.27 mmol) in water (2 mL) was added potassiumcarbonate (0.175 g, 1.27 mmol). The reaction mixture was cooled to 0° C.and phosgene (20% solution in toluene) (0.95 mL, 1.91 mmol) was slowlyadded dropwise. The resulting yellow solution was stirred for 16 h.Ethyl acetate (4 mL) was added and the layers were separated. Theaqueous layer was extracted with ethyl acetate (3×5 mL). The combinedorganic layers were dried over magnesium sulfate, filtered andconcentrated in vacuo. The crude product was purified by columnchromatography (Merck silica gel 60, 40-63 μm, ethyl acetate/hexane,20-50%) to afford the desired product,4-(3-methyl-butyl)-6-oxa-3a,4-diaza-indene-5,7-dione (0.16 g, 0.72 mmol,57% yield) as a tan solid. ¹H NMR (400 MHz, DMSO-d₆) δ 0.93 (6H, d,J=6.8 Hz), 1.56 (2H, m), 1.65 (1H, m), 4.16 (2H, t, J=7.2 Hz), 6.50 (1H,m), 7.08 (1H, m), 7.70 (1H, m).

(f)4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester

To a solution of 4-(3-methyl-butyl)-6-oxa-3a,4-diaza-indene-5,7-dione(Example 1e, 0.080 g, 0.36 mmol) and diethyl malonate (0.58 mL, 3.6mmol) in N,N-dimethylacetamide (1 mL) was added sodium hydride (0.017 g,0.43 mmol) and 1 drop of methanol. The reaction mixture was heated to120° C. and stirred for 16 h. The reaction was allowed to cool to 25° C.and quenched with saturated aqueous ammonium chloride solution and ethylacetate. The layers were separated and the aqueous layer was extractedwith ethyl acetate (3×3 mL). The combined organic layers were dried overmagnesium sulfate, filtered and concentrated in vacuo. The crude productwas purified by column chromatography (Merck silica gel 60, 40-63 μm,ethyl acetate/dichloromethane, 2-5%) to afford the desired product,4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (0.058 g, 0.20 mmol, 55% yield) as a light tan solid.¹H NMR (400 MHz, DMSO-d₆) δ 0.93 (6H, d, J=6.4 Hz), 1.30 (3H, t, J=6.8Hz), 1.49 (2H, q, J₁=15.2 Hz, J₂=7.6 Hz), 1.63 (1H, m), 4.23-4.30 (4H,m), 6.56 (1H, m), 6.87 (1H, m), 7.68 (1H, m); LC-MS (ESI) calcd forC₁₅H₂₀N₂O₄ 292.33. found 293.30 [M+H⁺].

(g)3-(1,1-Dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-4-hydroxy-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one

4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (Example 1f, 0.040 g, 0.14 mmol) was mixed with2-amino-benzenesulfonamide (0.0235 g, 0.14 mmol) and the resultingmixture was heated to 180° C. for 20 min. The resulting crude oil wasallowed to cool to 25° C. and ethanol (0.5 mL) was added and sonicatedto afford a tan precipitate, which was collected and dried in vacuo. Thecrude solid was dissolved in 1.0 M aqueous potassium hydroxide solution(0.3 mL) and heated to 110° C. for 20 h. The reaction mixture wasallowed to cool to 25° C. and 10% aqueous hydrochloric acid solution(0.5 mL) was added and the resulting white precipitate was collected.The solid was washed with methanol and dried in vacuo to afford thedesired product,3-(1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-4-hydroxy-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(0.028 g, 0.07 mmol, 52% yield) as a white solid. ¹H NMR (400 MHz,DMSO-d₆) δ 0.97 (6H, d, J=6.4 Hz), 1.28 (2H, bs), 1.61 (2H, q, J₁=15.2Hz, J₂=6.8 Hz), 1.74 (1H, m), 4.43 (2H, t, J=8.0 Hz), 6.71 (1H, dd,J₁=4.4 Hz, J₂=2.4 Hz), 7.04 (1H, d, J=4.4 Hz), 7.23 (1H, t, J=8.0 Hz),7.50 (1H, t, J=7.6 Hz), 7.63 (1H, d, J=8.4 Hz), 7.88 (1H, d, J=8.0 Hz),7.90 (1H, m); LC-MS (ESI) calcd for C₁₉H₂₀N₄O₄S 400.45. found 401.28[M+H⁺].

EXAMPLE 24-Hydroxy-3-(7-methoxy-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one

a) 7-Methoxy-1,1-dioxo-1,4-dihydro-2H-1λ⁶-benzo[1,2,4]thiadiazin-3-one

Chlorosulfonyl isocyanate (17 mL, 195 mmol) was dissolved in nitroethane(150 mL) and cooled to −40° C. A solution of 4-methoxyaniline (20 g, 162mmol) in nitroethane (100 mL) was then added dropwise with stirring.After the addition was completed, the reaction was stirred for anadditional 5 min and aluminum chloride (25 g, 195 mmol) was added. Themixture was then quickly heated to 110° C. with stirring for 20 min. Thecrude material was then poured onto ice and the precipitate wascollected by vacuum filtration, washed with cold water, and dried invacuo to afford the desired product,7-methoxy-1,1-dioxo-1,4-dihydro-2H-1λ⁶-benzo[1,2,4]thiadiazin-3-one (35g, 153.5 mmol, 79% yield) as a purple powder. ¹H NMR (400 MHz, DMSO-d₆):δ 3.6 (br, 1H), 3.78 (s, 3H), 7.2 (m, 3H), 11.05 (s, 1H).

b) 2-Amino-5-methoxy-benzenesulfonamide

A solution of7-methoxy-1,1-dioxo-1,4-dihydro-2H-1λ⁶-benzo[1,2,4]thiadiazin-3-one(Example 2a, 15 g, 65.7 mmol) in a 50% aqueous sulfuric acid solution(140 mL) was heated at 130° C. for 6 h. The solution was then pouredover ice and neutralized at 0° C. with the addition of saturated aqueoussodium hydroxide solution. The mixture was then extracted with ethylacetate. The organic phase was washed with brine, and dried overmagnesium sulfate, filtered and dried in vacuo to afford the desiredproduct, 2-amino-5-methoxy-benzenesulfonamide (8.1 g, 40.1 mmol, 61%yield) as a brown solid. See procedure described in Girard, Y., et al.,J. Chem. Soc. Perkin Trans 1, 1043-1047 (1979). ¹H NMR (400 MHz,DMSO-d₆): δ 3.65 (s, 3H), 5.40 (s, 2H), 6.73 (d, 1H, J=8.8 Hz), 6.90(dd, 1H, J₁=8.8 Hz, J₂=2.8 Hz), 7.07 (d, 1H, J=2.8 Hz), 7.19 (s, 2H).

c)4-Hydroxy-3-(7-methoxy-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one

4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (Example 1f, 0.040 g, 0.14 mmol) was mixed with2-amino-5-methoxy-benzenesulfonamide (Example 2b, 0.0235 g, 0.14 mmol)and the resulting mixture was heated to 180° C. for 20 min. Theresulting crude oil was allowed to cool to 25° C. and ethanol (0.5 mL)was added and sonicated to afford a tan precipitate, which was collectedand dried in vacuo. The crude solid was dissolved in 1.0 M aqueouspotassium hydroxide solution (0.5 mL) and heated to 110° C. for 12 h.The reaction mixture was allowed to cool to 25° C. and 10% aqueoushydrochloric acid solution (0.5 mL) was added and the resulting whiteprecipitate was collected. The crude solid was washed with methanol anddried in vacuo to afford the desired product,4-hydroxy-3-(7-methoxy-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(0.027 g, 0.063 mmol, 47% yield) as a white solid. ¹HNMR (400 MHz,DMSO-d₆) δ 1.07 (6H, d, J=6.4 Hz), 1.69 (1H, m), 1.78 (1H, m), 3.89 (3H,s), 4.39 (2H, t, J=7.6 Hz), 6.60 (1H, dd, J₁=4.4 Hz, J₂=2.8 Hz), 7.04(1H, d, J=4.4 Hz), 7.05 (1H, dd, J₁=4.8 Hz, J₂=2.0 Hz), 7.25 (1H, m),7.17 (1H, m), 7.39 (1H, d, J=2.0 Hz); LC-MS (ESI) calcd for C₁₉H₂₂N₄O₅S430.49. found 431.33 [M+H⁺].

EXAMPLE 3N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

a) N-(4-Nitro-phenyl)-methanesulfonamide

4-Nitro-phenylamine (25 g, 181 mmol) was dissolved in pyridine (450 mL).Methanesulfonyl chloride (14.0 mL, 181 mmol) was added dropwise whilestirring. The mixture was stirred for 16 h at 25° C. The solution wasconcentrated in vacuo to a volume of ˜50 mL. The mixture was dilutedwith ethyl acetate (400 mL), washed with 1.0 M aqueous hydrochloric acidsolution (5×200 mL). The combined aqueous layers were back-extractedwith ethyl acetate (200 mL). The combined organic layers were dried overmagnesium sulfate, filtered and concentrated in vacuo to a volume of˜250 mL. The product precipitated and was collected by vacuumfiltration. The filtrate was concentrated in vacuo to a volume of ˜125mL upon which additional product precipitated. The solid was collectedby vacuum filtration. The solids were combined to afford the desiredproduct, N-(4-nitro-phenyl)-methanesulfonamide (25 g, 115.62 mmol, 64%yield) as a pale yellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ 3.17 (3H, s),7.35 (2H, d, J=9.4 Hz), 8.20 (2H, d, J=9.1 Hz), 10.69 (1H, s).

b) N-(4-Amino-phenyl)-methanesulfonamide

N-(4-Nitro-phenyl)-methanesulfonamide (Example 3a, 25 g, 115.62 mmol)was dissolved in N,N-dimethylformamide (15 mL) with gentle heating to˜50° C. via heat gun. Ethyl acetate (100 mL) and methanol (100 mL) wereadded followed by 10% palladium on carbon (4 g). The mixture wasdegassed while stirring and the flask was charged with hydrogen gas viaballoon. The mixture was stirred at 25° C. for 4.5 h. The mixture wasfiltered through Celite (rinsed with ethyl acetate) and concentrated invacuo to a yellow green solution with a volume of ˜10 mL.Dichloromethane (˜50 mL) was added and a solid began to precipitate. Themixture was stirred at 25° C. for 30 min. The solid was collected byvacuum filtration and dried in vacuo to afford the desired product,N-(4-amino-phenyl)-methanesulfonamide (15.32 g, 82.26 mmol, 71% yield)as a beige powder. ¹H NMR (400 MHz, DMSO-d₆) δ 2.79 (3H, s), 5.00 (2H,s), 6.49 (2H, d, J=8.5 Hz), 6.87 (2H, d, J=8.6 Hz), 8.87 (1H, s).

c)N-(1,1,3-Trioxo-1,2,3,4-tetrahydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl)-methanesulfonamide

Chloro-sulfonyl-isocyanate (1.7 mL, 19.6 mmol) was dissolved innitroethane (10 mL) and chilled to −40° C. under nitrogen.N-(4-Amino-phenyl)-methanesulfonamide (Example 3b, 3g, 16.1 mmol) wasadded dropwise as a pre-dissolved solution in nitroethane (25 mL). Themixture was stirred at −40° C. for 15 min. Aluminum chloride (8 g, 60mmol) was added and the mixture was heated at 110° C. for 30 min whilestirring. The mixture was poured onto ice (150 g). Upon melting, theproduct was extracted into ethyl acetate (5×250 mL). The combinedorganic layers were dried over magnesium sulfate, filtered andconcentrated in vacuo to afford the desired product,N-(1,1,3-trioxo-1,2,3,4-tetrahydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl)-methanesulfonamide(3.63 g, 12.46 mmol, 77% yield) as a beige solid. ¹H NMR (400 MHz,DMSO-d₆) δ 3.00 (3H, s), 7.22 (1H, d, J=8.5 Hz), 7.46 (1H, dd, J₁=8.8Hz, J₂=2.7 Hz), 7.51 (1H, d, J=2.4 Hz), 9.92 (1H, s), 11.20 (1H, s).

d) 2-Amino-5-methanesulfonylamino-benzenesulfonamide

N-(1,1,3-Trioxo-1,2,3,4-tetrahydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl)-methanesulfonamide(Example 3c, 1g, 3.4 mmol) was suspended in 12 M aqueous hydrochloricacid solution (60 mL). The mixture was stirred at 105° C. for 16 h. Allsolids were dissolved at this point. The mixture was diluted with water(250 mL). The solution was concentrated in vacuo to an orange solid. Thesolid was dissolved in water (20 mL) and concentrated in vacuo to anorange solid. The solid was dissolved in water (5 mL) and the productwas extracted into ethyl acetate (6×20 mL). The combined organic phasewas dried over magnesium sulfate, filtered and concentrated in vacuo toan orange solid. Purification by flash column chromatography (Mercksilica gel 60, 40-63 μm, 75% ethyl acetate in hexanes) afforded thedesired product, 2-amino-5-methanesulfonylamino-benzenesulfonamide (0.41g, 1.55 mmol, 45% yield), as a beige solid. ¹H NMR (400 MHz, DMSO-d₆) δ2.86 (3H, s), 5.77 (2H, s), 6.76 (1H, d, J=8.6 Hz), 7.11 (1H, dd, J₁=8.6Hz, J₂=2.4 Hz), 7.25 (2H, bs), 7.43 (1H, d, J=3.1 Hz), 9.16 (1H, s).

Alternatively, the 2-amino-5-methanesulfonylamino-benzenesulfonamideintermediate of 3(d) above was preferrably made according to thefollowing procedure:

(a)′: N-(4-Nitro-phenyl)-methanesulfonamide

A solution of methanesulfonylchloride (47.1 mL, 0.61 mol) inacetonitrile (160 mL) was added over 40 min to a solution of4-nitroaniline (80.0 g, 0.58 mol) and pyridine (70.2 mL, 0.87 mol) inacetonitrile (400 mL) at 25° C. The mixture was stirred at 25° C. for 19h, and then water (800 mL) was added. The resulting suspension wasstirred at 25° C. for 30 min, and then was filtered through medium paperusing a Büchner funnel. The collected solid was washed with water (2×150mL) and air-dried overnight to afford the desired product,N-(4-nitro-phenyl)-methanesulfonamide (111.4 g, 0.52 mol, 89% yield) asa pale yellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ 3.17 (3H, s), 7.35 (2H,d, J=9.4 Hz), 8.20 (2H, d, J=9.1 Hz), 10.69 (1H, s).

(b)′: N-(4-Amino-phenyl)-methanesulfonamide

5% Palladium on carbon (“wet”, 11.1 g) was added to a solution ofN-(4-nitro-phenyl)-methanesulfonamide (Example 3a′, 111.4 g, 0.52 mol)in tetrahydrofuran (900 mL) at 25° C. The atmosphere above the resultingsuspension was replaced with hydrogen gas and the reaction mixture wasmaintained under 1 atmosphere of hydrogen at 25° C. for 4 days usingseveral balloons. The mixture was then filtered through Celite and theCelite was washed with tetrahydrofuran (3×100 mL). The combined filtrateand washings were concentrated in vacuo to approximately 300 mL volumeand heptane (500 mL) was added dropwise via addition funnel over 45 minat 25° C. with vigorous stirring. The resulting suspension was stirredfor an additional 45 min at 25° C., and then was filtered through mediumpaper using a Büchner funnel. The collected solid was washed withheptane (1×150 mL) and was air-dried to afford the desired product,N-(4-amino-phenyl)-methanesulfonamide (90.7 g, 0.49 mol, 95% yield) as abeige powder. ¹H NMR (400 MHz, DMSO-d₆) δ 2.79 (3H, s), 5.00 (2H, s),6.49 (2H, d, J=8.5 Hz), 6.87 (2H, d, J=8.6 Hz), 8.87 (1H, s).

(c)′:N-(1,1,3-Trioxo-1,2,3,4-tetrahydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl)-methanesulfonamide

A solution of N-(4-amino-phenyl)-methanesulfonamide (Example 3b′, 90.7g, 0.49 mol) in nitroethane (900 mL) was added dropwise over 1.5 h to amechanically stirred solution of chlorosulfonylisocyanate (50.6 mL, 0.54mol) in nitroethane (150 mL) at −20° C. The resulting suspension wasstirred at −20° C. for 30 min, then aluminum chloride (77.9 g, 0.58 mol)was added in one portion over 1 min. The resulting brown solution waswarmed to 25° C., and then was heated at 110° C. for 1 h (considerablegas evolution was noted during this time). After cooling to −5° C.,water (300 mL) was added dropwise via addition funnel over 15 min,followed by the rapid addition of more water (700 mL). The resultingsuspension was allowed to warm to 25° C. and vigorously stirred for 30min, and then was filtered through medium paper using a Büchner funnel.The collected solid was washed with water (1×300 mL) and was air-driedto afford the desired product,N-(1,1,3-trioxo-1,2,3,4-tetrahydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl)-methanesulfonamide(115.2 g, 0.40 mmol, 81% yield) as a beige solid. ¹H NMR (400 MHz,DMSO-d₆) δ 3.00 (3H, s), 7.22 (1H, d, J=8.5 Hz), 7.46 (1H, dd, J₁=8.8Hz, J₂=2.7 Hz), 7.51 (1H, d, J=2.4 Hz), 9.92 (1H, s), 11.20 (1H, s).

(d)′: 2-Amino-5-methanesulfonylamino-benzenesulfonamide

A mechanically stirred suspension ofN-(1,1,3-trioxo-1,2,3,4-tetrahydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl)-methanesulfonamide(Example 3c′, 115.2 g, 0.40 mol) in 9.0 M aqueous sulfuric acid (500 mL)was heated to 130° C. for 2.5 h (considerable gas evolution was notedduring this time). The resulting brown solution was cooled to 0° C. andan aqueous solution of sodium hydroxide (351 g in 750 mL water; ca. 11.7M) was added via addition funnel over 45 min. The pH of the reactionmixture was then adjusted to approximately 7.0 by the dropwise additionof 3.0 M aqueous sodium carbonate solution. The resulting suspension wasallowed to warm to 25° C. and stirred for 1 h, then was filtered throughmedium paper using a Büchner funnel. The collected solid was washed withwater (1×300 mL) and was dried in a vacuum oven at 50° C. to afford amixture of 2-amino-5-methanesulfonylamino-benzenesulfonamide and2,5-diamino-benzenesulfonamide (1.5:1.0 ratio, 70.0 g, 75% yield) as abrown solid. ¹H NMR (400 MHz, DMSO-d₆) δ: 2.86 (3H, s), 4.54 (2H, bs),4.98 (2H, bs), 5.77 (2H, s), 6.55-6.60 (2H, m), 6.76 (1H, d, J=8.6 Hz),6.87 (1H, d, J=2.2 Hz), 6.99 (2H, bs), 7.11 (1H, dd, J₁=8.6 Hz, J₂=2.4Hz), 7.25 (2H, bs), 7.43 (1H, d, J=3.1 Hz), 9.16 (1H, s).

A solution of methanesulfonylchloride (8.2 mL, 0.11 mol) in acetonitrile(100 mL) was added over 15 min to a solution of the above mixture of2-amino-5-methanesulfonylamino-benzenesulfonamide and2,5-diamino-benzenesulfonamide (1.5:1.0 ratio, 60.0 g) and pyridine(12.0 mL, 0.15 mol) in acetonitrile (500 mL) at 25° C. The mixture wasstirred at 25° C. for 15 h, and then was concentrated in vacuo toapproximately 300 mL volume. Ethyl acetate (300 mL) was added and theresulting suspension was stirred at 25° C. for 10 min, and then wasfiltered through medium paper using a Büchner funnel. The collectedsolid was washed with water (1×200 mL) and was dried in a vacuum oven at50° C. to afford the desired product,2-amino-5-methanesulfonylamino-benzenesulfonamide (54.0 g, 0.20 mol, 80%yield) as a beige solid. ¹H NMR (400 MHz, DMSO-d₆) δ 2.86 (3H, s), 5.77(2H, s), 6.76 (1H, d, J=8.6 Hz), 7.11 (1H, dd, J₁=8.6 Hz, J₂=2.4 Hz),7.25 (2H, bs), 7.43 (1H, d, J=3.1 Hz), 9.16 (1H, s).

e)N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (Example 1f, 0.098 g, 0.33 mmol) and2-amino-5-methanesulfonylamino-benzenesulfonamide (Example 3d or Example3d′, 0.089 g, 0.33 mmol) were mixed in pyridine (1.5 mL) and the mixturewas stirred under a nitrogen atmosphere at 120° C. for 3 h. LC-MSanalysis confirmed the disappearance of the starting material and theformation of the uncyclized intermediate4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid (4-methanesulfonylamino-2-sulfamoyl-phenyl)-amide.1,8-Diazabicyclo[5,4,0]undec-7-ene (DBU) (150 μL, 1.0 mmol) was addedand the mixture was stirred under nitrogen atmosphere at 120° C. for 16h. LC-MS analysis indicated completion of the reaction and the mixturewas concentrated in vacuo. The crude material was dissolved indimethylsulfoxide and purified by preparative HPLC (Column ODS-A 100 Å,5μ. 150×21.2 mm. Flow 22 mL/min, 30-100% acetonitrile/water with 0.01%trifluoroacetic acid) and lyophilized from water and 1,4-dioxane toafford the desired product,N-{3-[4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide(0.016 g, 0.032 mmol, 9.7% yield) as a light brown powder. ¹H NMR(DMSO-d₆) δ 0.96 (6H, d, J=6.3 Hz), 1.55-1.60 (2H, m), 1.67-1.77 (1H,m), 3.07 (1H, s), 4.40 (2H, t, J=7.8 Hz), 6.70 (1H, s), 7.02 (1H, s),7.52-7.67 (3H, m), 7.90 (1H, s), 10.20 (1H, s); LC-MS (ESI) calcd forC₂₀H₂₃N₅O₆S₂ 493.1 found 494.3 [M+H⁺].

EXAMPLE 4N-{3-[1-(3,3-Dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

a) 2-Amino-5-iodo-benzenesulfonamide

2-Amino-benzenesulfonamide (5.15 g, 29.3 mmol) was dissolved inchloroform (87 mL), and N-iodosuccinimide (7.29 g, 30.77 mmol) was addedunder a nitrogen atmosphere. The mixture was heated at reflux for 24 h,allowed to cool to 25° C., and filtered through a sinter funnel. Thesolid was washed with chloroform and 10% methanol/chloroform (3-8 times)to afford the desired product, 2-amino-5-iodo-benzenesulfonamide (6.78g, 22.75 mmol, 78% yield) as a brown crystalline solid. ¹H NMR (400 MHz,DMSO-d₆): 5.98 (s, 2H), 6.62 (d, 1H, J=8.8 Hz), 7.31 (s, 2H), 7.45 (dd,1H, J=8.8, 2.4 Hz), 7.73 (d, 1H, J=2.0 Hz).

b) (7-Iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid

2-Amino-5-iodo-benzenesulfonamide (Example 4a, 2.0 g, 6.71 mmol) wasdissolved in N,N-dimethylacetamide (5 mL) and diethyl ether (7 mL).Ethyl 3-chloro-3-oxo-propionate (0.916 g, 6.71 mmol) was added and thereaction mixture was stirred at 25° C. for 2 h. The reaction mixture wasdiluted with diethyl ether (10 mL) and water (20 mL). Upon mixingvigorously, a precipitate formed. The solid was collected by vacuumfiltration, rinsed with 1.0 M aqueous hydrochloric acid solution (2×10mL) and dried in vacuo for 2 h. The solid was dissolved in 8% aqueoussodium hydroxide solution (50 mL) and stirred at 100° C. for 15 min.Upon cooling to 25° C., the solution was neutralized with 6.0 M aqueoushydrochloric acid solution. Additional 1.0 M aqueous hydrochloric acidsolution (20 mL) was added and the desired product precipitated. Thesolid was collected by vacuum filtration, rinsed with 1.0 M aqueoushydrochloric acid solution (2×10 mL) and dried in vacuo for 16 h toafford the desired product,(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid (2.0 g, 5.46 mmol, 81% yield) as a pale pink powder. ¹HNMR (400MHz, DMSO-d₆) δ: 3.58 (3H, s), 7.13 (1H, d, J=8.5 Hz), 7.98 (1H, dd,J₁=8.6 Hz, J₂=1.7 Hz), 8.03 (1H, d, J=2.5 Hz), 12.33 (1H, bs), 13.05(1H, bs). LC-MS (ESI) calcd for C₉H₇IN₂O₄S 365.92. found 366.95 [M+H⁺].

c) 1-(3,3-Dimethyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester

Dimethylsulfoxide (6.80 mL, 95.7 mmol) was added over 5 min to asolution of oxalylchloride (23.9 mL, 47.8 mmol) in dichloromethane at−78° C. The resulting mixture was stirred at −78° C. for 5 min, then3,3-dimethyl-butan-1-ol (5.22 mL, 43.1 mmol) was added. After stirringan additional 30 min at −78° C., triethylamine (23.3 mL, 167 mmol) wasadded and the reaction mixture warmed to 0° C. and stirred at thattemperature for 45 min. The mixture was then transferred to a separatoryfunnel and was washed with 0.5 M aqueous hydrochloric acid. The organiclayer was dried over sodium sulfate, filtered and was concentrated invacuo to a volume of about 70 mL (water bath temperature=0° C.).Methanol (100 mL) was added followed sequentially by1-amino-1H-pyrrole-2-carboxylic acid allyl ester (Example 1b, 7.16 g,43.1 mmol), acetic acid (6 mL), and sodium cyanoborohydride (5.42 g,86.3 mmol). The reaction mixture was stirred at 23° C. for 2 h, and thenwas partitioned between saturated aqueous sodium bicarbonate solution(400 mL) and a 1:1 mixture of ethyl acetate and hexanes (2×200 mL). Theorganic layers were dried over sodium sulfate, filtered and concentratedin vacuo. Purification of the residue by flash column chromatography(Merck silica gel 60, 40-63 μm, 5-10% ethyl acetate in hexanes) affordedthe desired product, 1-(3,3-dimethyl-butylamino)-1H-pyrrole-2-carboxylicacid allyl ester (4.04 g, 16.15 mmol, 37% yield) as a clear liquid.¹HNMR (400 MHz, CDCl₃) δ: 0.91 (9H, s), 1.42-1.46 (2H, m), 2.98-3.04(2H, m), 4.75-4.77 (2H, m), 5.26-5.28 (1H, m), 5.37-5.41 (1H, m),5.96-5.99 (1H, m), 6.01-6.05 (1H, m), 6.27-6.30 (1H, m), 6.89-6.91 (1H,m), 6.96-6.98 (1H, m).

d)1-(3,3-Dimethyl-butyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one

(7-Iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid (Example 4b, 0.3 g, 0.819 mmol) was dissolved inN,N-dimethylformamide (4.1 mL).1-(3,3-Dimethyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester(Example 4c, 0.205 g, 0.819 mmol) was added followed by a 1.0 M solutionof N,N-dicyclohexylcarbodiimide in dichloromethane (0.860 mL, 0.86mmol). The mixture was stirred at 25° C. for 2 h. N,N-Dicyclohexylureaprecipitation was visible at this point. The mixture was diluted withdichloromethane (5 mL) and filtered under reduced pressure. The filtratewas washed with 1.0 M aqueous hydrochloric acid solution (2×10 mL),saturated aqueous brine solution (10 mL), dried over magnesium sulfate,filtered and concentrated in vacuo to afford a golden oil. The oil wasdissolved in ethanol (4.1 mL). A 21% solution of sodium ethoxide inethanol (0.673 mL) was added and the mixture was stirred at 80° C. for 4h. Additional sodium ethoxide in ethanol (0.673 mL) was added and themixture was stirred at 80° C. for 4 h. Upon cooling to 25° C., the pHwas adjusted to approximately 6 by the addition of 3.0 M aqueoushydrochloric acid solution. Immediate precipitation was observed.Methanol (3 mL) was added and the mixture was shaken vigorously. Thesolid was collected by vacuum filtration, rinsed with methanol (3×2 mL)and dried in vacuo for 16 h to afford the desired product,1-(3,3-dimethyl-butyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one(0.268 g, 0.67 mmol, 82% yield) as a white powder. LC-MS (ESI) calcd forC₂₀H₂₁IN₄O₄S. found 540.03. found 366.95 [M+H⁺].

e)N-{3-[1-(3,3-Dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

1-(3,3-Dimethyl-butyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one(Example 4d, 0.065 g, 0.120 mmol), potassium triphosphate (0.128 g, 0.60mmol), sarcosine (0.006 g, 0.072 mmol), and copper (I) iodide (0.006 g,0.03 mmol) were combined. Anhydrous N,N-dimethylformamide (2 mL) wasadded followed by methanesulfonamide (0.114 g, 1.2 mmol). The solutionwas degassed while stirring under vacuum and the flask was purged withnitrogen. The mixture was stirred at 100° C. for 2 h. Upon cooling, themixture was diluted with ethyl acetate (100 mL), washed with 1.0 Maqueous hydrochloric acid solution (3×50 mL) and dried over magnesiumsulfate. The entire organic layer was passed through a plug of silicagel. The filtrate was concentrated in vacuo to afford a solid. The solidwas triturated with a 1:1 mixture of ethyl acetate and hexanes,collected by vacuum filtration, triturated with methanol and collectedby vacuum filtration. The solid was dried in vacuo for 16 h to affordthe desired product,N-{3-[1-(3,3-dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide(0.031 g, 0.061 mmol, 51% yield) as a pale yellow powder. ¹H NMR (400MHz, DMSO-d₆) δ: 1.01 (9H, s), 1.57-1.62 (2H, m), 3.07 (3H, s),4.39-4.43 (2H, m), 6.70-6.72 (1H, m), 7.03 (1H, d, J=3.8 Hz), 7.53 (1H,dd, J₁=8.7 Hz, J₂=2.8 Hz), 7.60 (1H, d, J=2.3 Hz), 7.67 (1H, d, J=8.4Hz), 7.75 (1H, s), 10.20 (1H, s), 13.72 (1H, bs). LC-MS (ESI) calcd forC₂₁H₂₅N₅O₆S₂. found 507.12. found 508.36 [M+H⁺].

EXAMPLE 5N-{3-[1-(3,3-Dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-N-methyl-methanesulfonamide

1-(3,3-Dimethyl-butyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one(Example 4d, 0.257 g, 0.476 mmol), potassium triphosphate (0.505 g, 2.38mmol), sarcosine (0.025 g, 0.285 mmol), and copper (J) iodide (0.022 g,0.119 mmol) were combined. Anhydrous N,N-dimethylformamide (9.5 mL) wasadded followed by N-methyl-methanesulfonamide (0.519 g, 4.76 mmol). Thesolution was degassed while stirring under vacuum and the flask purgedwith nitrogen. The mixture was stirred at 100° C. for 1 h. Additionalcopper (I) iodide (0.1 g, 0.525 mmol) was added. The mixture continuedto stir at 100° C. for 3 h. Upon cooling, the mixture was diluted withethyl acetate (200 mL), washed with 1.0 M aqueous hydrochloric acidsolution (2×100 mL), dried over magnesium sulfate. The entire organiclayer was passed through a plug of silica gel. Upon concentrating invacuo to a volume of approximately 10 mL, the desired productprecipitated. The solid was collected by vacuum filtration. The solidwas recrystallized in ethyl acetate, collected by vacuum filtration anddried in vacuo to afford the desired product,N-{3-[1-(3,3-dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-N-methyl-methanesulfonamide(0.082 g, 0.157 mmol, 33% yield) as a pale yellow powder. ¹H NMR (400MHz, DMSO-d₆) δ: 1.02 (9H, s), 1.58-1.62 (2H, m), 3.01 (3H, s), 3.31(3H, s), 4.40-4.44 (2H, m), 6.72-6.72 (1H, m), 7.04 (1H, d, J=3.9 Hz),7.70-7.76 (3H, m), 7.88 (1H, s), 13.78 (1H, bs). LC-MS (ESI) calcd forC₂₂H₂₇N₅O₆S₂. found 521.14. found 522.6 [M+H⁺].

EXAMPLE 6N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-N-methyl-methanesulfonamide

a)4-Hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one

(7-Iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid (Example 4b, 0.2 g, 0.546 mmol) was dissolved inN,N-dimethylformamide (2.7 mL).1-(3-Methyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester(Example 1c, 0.129 g, 0.546 mmol) was added followed by a 1.0 M solutionof N,N-dicyclohexylcarbodiimide in dichloromethane (0.574 mL, 0.574mmol). The mixture was stirred at 25° C. for 2 h. N,N-Dicyclohexylureaprecipitation was visible at this point. The mixture was diluted withdichloromethane (5 mL) and filtered under reduced pressure. The filtratewas washed with 1.0 M aqueous hydrochloric acid solution (2×10 mL),saturated aqueous brine solution (10 mL), dried over magnesium sulfate,filtered and concentrated in vacuo to afford a golden oil. The oil wasdissolved in ethanol (2.7 mL). A 21% solution of sodium ethoxide inethanol (0.448 mL) was added and the mixture was stirred at 80° C. for 4h. Additional sodium ethoxide in ethanol (0.448 mL) was added and themixture was stirred at 80° C. for 4 h. Upon cooling to 25° C., the pHwas adjusted to approximately 6 by the addition of 3.0 M aqueoushydrochloric acid solution. Immediate precipitation was observed.Methanol (3 mL) was added and the mixture was shaken vigorously. Thesolid was collected by vacuum filtration, rinsed with methanol (3×2 mL)and dried in vacuo for 16 h to afford the desired product,4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(0.196 g, 0.372 mmol, 68% yield) as a white powder. LC-MS (ESI) calcdfor C₁₉H₁₉IN₄O₄S. found 526.02. found 527.15 [M+H⁺].

b)N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-N-methyl-methanesulfonamide

4-Hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(Example 6a, 0.188 g, 0.357 mmol), potassium triphosphate (0.379 g, 1.78mmol), sarcosine (0.019 g, 0.214 mmol), and copper (I) iodide (0.017 g,0.089 mmol) were combined. Anhydrous N,N-dimethylformamide (7 mL) wasadded followed by N-methyl-methanesulfonamide (0.39 g, 3.57 mmol). Thesolution was degassed while stirring under vacuum and the flask purgedwith nitrogen. The mixture was stirred at 100° C. for 1 h. Additionalcopper (I) iodide (0.1 g, 0.525 mmol) was added. The mixture continuedto stir at 100° C. for 3 h. Upon cooling, the mixture was diluted withethyl acetate (200 mL), washed with 1.0 M aqueous hydrochloric acidsolution (2×100 mL), dried over magnesium sulfate, filtered andconcentrated in vacuo to a solid. Purification by flash columnchromatography (5% ethyl acetate in dichloromethane) followed bytrituration from ethyl acetate and collection by vacuum filtrationafforded the desired product,N-{3-[4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-N-methyl-methanesulfonamide(0.057 g, 0.112 mmol, 31% yield) as a pale yellow powder. ¹H NMR (400MHz, DMSO-d₆) δ: 0.97 (6H, d, J=6.4 Hz), 1.59 (2H, q, J=7.6 Hz), 1.73(1H, septet, J=6.5 Hz), 3.01 (3H, s), 3.31 (3H, s), 4.41 (2H, t, J=7.9Hz), 6.70-6.72 (1H, m), 7.04 (1H, d, J=4.5 Hz), 7.69-7.76 (2H, m), 7.88(1H, d, J=2.3 Hz), 7.91 (1H, s), 13.79 (1H, bs). LC-MS (ESI) calcd forC₂₁H₂₅N₅O₆S₂. found 507.12. found 508.4 [M+H⁺].

EXAMPLE 7N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-N-methyl-methanesulfonamide

a) N-Benzothiazol-6-yl-methanesulfonamide

Methanesulfonyl chloride (4.93 mL, 63.7 mmol) was added over 5 min to asolution of benzothiazol-6-ylamine (9.58 g, 63.8 mmol) in pyridine (100mL) at 25° C. The resulting mixture was stirred at 25° C. for 30 min,and then was concentrated in vacuo. The residue was partitioned between1.0 M aqueous hydrochloric acid solution (150 mL) and ethyl acetate(2×150 mL). The organic layers were dried over sodium sulfate, filteredand concentrated in vacuo. Trituration of the residue with diethyl etherafforded a solid that was collected by vacuum filtration and dried invacuo to afford the desired product,N-benzothiazol-6-yl-methanesulfonamide (13.3 g, 58.3 mmol, 91% yield) asa pink solid. ¹HNMR (400 MHz, DMSO-d₆) δ: 3.03 (3H, s), 7.36 (1H, dd,J₁=2.3 Hz, J₂=8.6 Hz), 7.94 (1H, d, J=1.6 Hz), 8.02 (1H, d, J=9.2 Hz),9.27 (1H, s), 9.95 (1H, s).

b) N-Benzothiazol-6-yl-N-methyl-methanesulfonamide

Sodium hydride (2.56 g of a 60% dispersion in mineral oil, 64.0 mmol)was added to a solution of N-benzothiazol-6-yl-methanesulfonamide(Example 7a, 13.3 g, 58.2 mmol) in tetrahydrofuran at 0° C. After 15min, iodomethane (36.2 mL, 581 mmol) was added and the reaction mixturewas warmed to 25° C., stirred for 4 h, then was partitioned between 1.0M aqueous hydrochloric acid solution (300 mL) and ethyl acetate (2×250mL). The organic layers were dried over sodium sulfate, filtered andconcentrated in vacuo. Trituration of the residue with diethyl etherafforded a solid that was collected by vacuum filtration and dried invacuo to afford the desired product,N-benzothiazol-6-yl-N-methyl-methanesulfonamide (12.1 g, 50 mmol, 86%yield) as a pink solid. ¹H NMR (400 MHz, DMSO-d₆) δ: 3.00 (3H, s), 3.31(3H, s), 7.57 (1H, dd, J₁=2.2 Hz, J₂=8.7 Hz), 8.07 (1H, d, J=8.5 Hz),8.23 (1H, d, J=1.7 Hz), 9.40 (1H, s).

c) [7-(Methanesulfonyl-methyl-amino)-4H-benzo[1,4]thiazin-3-yl]-aceticacid methyl ester

Hydrazine monohydrate (20.1 mL, 414 mmol) was added to a solution ofN-benzothiazol-6-yl-N-methyl-methanesulfonamide (Example 7b, 10.06 g,41.5 mmol) in ethanol (150 mL) at 25° C. The reaction mixture was heatedto 50° C. for 13 h, and then was concentrated in vacuo. The residue wasdissolved in 1.0 M aqueous hydrochloric acid solution (100 mL) and thepH was adjusted to 7 by the addition of 6.0 M aqueous hydrochloric acidsolution. The resulting mixture was extracted with ethyl acetate (2×150mL) and the aqueous layer was acidified to pH 3 by the addition of 6.0 Maqueous hydrochloric acid solution, and then neutralized to pH 7 by theaddition of solid sodium bicarbonate. The mixture was again extractedwith ethyl acetate (1×150 mL) and all organic layers were combined,dried over sodium sulfate, filtered and concentrated in vacuo. Theorange solid thus obtained was dissolved in tetrahydrofuran (150 mL) andtriethylamine (12.3 mL, 88.2 mmol), and 4-chloro-3-oxo-butyric acidmethyl ester (5.10 mL, 44.2 mmol) were added sequentially at 25° C. Thereaction mixture was stirred at 25° C. for 2 h, and then was partitionedbetween 1.0 M aqueous hydrochloric acid solution (150 mL) and ethylacetate (2×150 mL). The organic layers were dried over sodium sulfate,filtered and concentrated in vacuo. Purification of the residue by flashcolumn chromatography (Merck silica gel 60, 40-63 μm, 20→100% ethylacetate in hexanes) afforded the desired product,[7-(methanesulfonyl-methyl-amino)-4H-benzo[1,4]thiazin-3-yl]-acetic acidmethyl ester (8.40 g, 25.6 mmol, 64% yield) as a yellow solid. ¹H NMR(400 MHz, CDCl₃) δ: 2.86 (3H, s), 3.27 (3H, s), 3.43 (2H, s), 3.72 (3H,s), 6.86 (1H, d, J=8.6 Hz), 7.12 (1H, dd, J₁=2.3 Hz, J₂=8.6 Hz), 7.21(1H, d, J=2.4 Hz), 10.63 (1H, s).

d)7-(Methanesulfonyl-methyl-amino)-3-methoxycarbonylmethyl-1,1-dioxo-1H-1λ⁶-benzo[1,4]thiazine-4-carboxylicacid tert-butyl ester

Di-tert-butyl carbonate (11.2 g, 51.1 mmol) and 4-dimethylaminopyridine(0.625 g, 5.11 mmol) were added sequentially to a solution of[7-(methanesulfonyl-methyl-amino)-4H-benzo[1,4]thiazin-3-yl]-acetic acidmethyl ester (Example 7c, 8.40 g, 25.6 mmol) in tetrahydrofuran (100 mL)at 25° C. The reaction mixture was stirred at 25° C. for 15 h, and thenwas partitioned between 1.0 M aqueous hydrochloric acid solution (150mL) and ethyl acetate (2×150 mL). The organic layers were dried oversodium sulfate, filtered and concentrated in vacuo. The residue wasdissolved in dichloromethane (150 mL) at 25° C. and m-chloroperbenzoicacid (17.2 g, 77% maximum purity, 76.7 mmol) was added. After stirringfor 50 min at 25° C., sodium thiosulfate (15 g, dissolved in 150 mLwater) was added and the biphasic mixture was stirred at 25° C. for 30min then poured into a separatory funnel containing a 1:1 mixture ofethyl acetate and hexanes (350 mL). The phases were separated and theorganic layer was washed sequentially with 1.0 M aqueous sodiumhydroxide solution (100 mL), 1.0 M aqueous hydrochloric acid solution(100 mL), and saturated aqueous sodium bicarbonate solution (100 mL).The organic layer was dried over sodium sulfate, filtered and wasconcentrated in vacuo. Purification of the residue by flash columnchromatography (Merck silica gel 60, 40-63 μm, 20-90% ethyl acetate inhexanes) afforded the desired product,7-(methanesulfonyl-methyl-amino)-3-methoxycarbonylmethyl-1,1-dioxo-1H-1λ⁶-benzo[1,4]thiazine-4-carboxylicacid tert-butyl ester (4.29 g, 9.32 mmol, 36% yield) as a yellow foam.¹H NMR (400 MHz, CDCl₃) (mixture of several isomers/tautomers) δ: 1.51(s), 1.54 (s), 1.55 (s), 2.87 (s), 2.88 (s), 3.35 (s), 3.37 (s), 3.71(s), 3.83 (s), 3.87 (s), 5.88 (s), 6.39 (s), 7.64-7.68 (m), 7.77-7.78(m), 7.83-7.85 (m), 10.02 (s).

e)[7-(Methanesulfonyl-methyl-amino)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl]-aceticacid

A 2.0 M aqueous solution of lithium hydroxide (7.0 mL, 14.0 mmol) wasadded to a solution of7-(methanesulfonyl-methyl-amino)-3-methoxycarbonylmethyl-1,1-dioxo-1H-1λ⁶-benzo[1,4]thiazine-4-carboxylicacid tert-butyl ester (Example 7d, 1.29 g, 2.80 mmol) in methanol at 25°C. The reaction mixture was stirred at 25° C. for 5 h, and then waspartitioned between 0.5 M aqueous hydrochloric acid solution (150 mL)and ethyl acetate (2×150 mL). The organic layers were dried over sodiumsulfate, filtered and concentrated in vacuo. Trituration of the residuewith a 5:1 mixture of diethyl ether and acetonitrile afforded thedesired product,[7-(methanesulfonyl-methyl-amino)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl]-aceticacid (0.286 g, 0.83 mmol, 30% yield) as an orange solid. ¹H NMR (400MHz, DMSO-d₆) δ: 2.96 (3H, s), 3.26 (3H, s), 3.48 (2H, s), 6.03 (1H, s),7.29 (1H, d, J=8.6 Hz), 7.58 (1H, dd, J₁=2.3 Hz, J₂=9.5 Hz), 7.79 (1H,d, J=2.3 Hz), 10.80 (1H, s), 12.79 (1H, s).

f)N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-N-methyl-methanesulfonamide

1-(3-Methyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester(Example 1c, 0.112 g, 0.473 mmol) and[7-(methanesulfonyl-methyl-amino)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl]-aceticacid (Example 7e, 0.164 g, 0.473 mmol) were dissolved in a 3:1 mixtureof dichloromethane and N,N-dimethylformamide (4 mL) at 25° C. A solutionof N,N-dicyclohexylcarbodiimide (0.473 mL, 1.0 M in dichloromethane,0.473 mmol) was added and the reaction mixture was stirred at 25° C. for1 h then filtered. The filtrate was concentrated in vacuo and theresidue was dissolved in ethanol (4 mL) at 25° C. A 21% solution ofsodium ethoxide in ethanol (0.368 mL, 1.14 mmol) was added and thereaction mixture was heated at 80° C. for 6 h. After cooling to 25° C.,the mixture was partitioned between 0.5 M aqueous hydrochloric acidsolution (150 mL) and ethyl acetate (2×150 mL). The organic layers weredried over sodium sulfate, filtered and concentrated in vacuo.Sequential purification of the residue by flash column chromatography(Merck silica gel 60, 40-63 μm, 5{tilde over (0)}→100% ethyl acetate inhexanes) and preparative HPLC [column=Luna 5μ C18(2) 100 Å Axia 50×21.2mm Id; eluent=0→100% acetonitrile in water (both containing 0.05%trifluoroacetic acid) over 7.0 min, flow=30 mL/min] afforded the desiredproduct,N-{3-[4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-N-methyl-methanesulfonamide(0.060 g, 0.119 mmol, 25% yield) as a yellow solid. ¹H NMR (400 MHz,DMSO-d₆) δ: 0.94 (6H, d, J=6.4 Hz), 1.50-1.54 (2H, m), 1.64-1.70 (1H,m), 2.99 (3H, bs), 3.28 (3H, bs), 4.29-4.32 (2H, m), 5.74 (1H, s), 6.12(1H, bs), 6.49 (1H, bs), 6.90 (1H, bs), 7.30 (1H, bs), 7.60 (1H, bs),7.82 (1H, bs). LC-MS (ESI) calcd for C₂₂H₂₆N₄O₆S₂ 506.13. found 507.25[M+H⁺].

EXAMPLE 8N-{3-[1-(3,3-Dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-methanesulfonamide

a) 2-Amino-5-nitro-benzenethiol

A solution of 6-nitrobenzothiazole (5 g, 27.7 mmol) in ethanol (50 mL)was treated with mono hydrazine hydrate (19 g, 388 mmol). The reactionmixture was stirred for 3 h at 25° C. and concentrated in vacuo. Theresulting red oil was taken up in ethyl acetate, carefully acidifiedwith 0.1 M aqueous hydrochloric acid solution until the solution turnedlight yellow. The reaction mixture was extracted with ethyl acetate,dried over magnesium sulfate, filtered, and concentrated in vacuo. Theresulting orange solid was triturated with diethyl ether and dried invacuo to afford the desired product, 2-amino-5-nitro-benzenethiol (4.1g, 23.9 mmol, 86% yield) as a yellow solid. ¹H NMR (400 MHz, Acetone-d₆)δ 6.43 (bs, 2H), 6.82 (d, 1H, J=8.7 Hz), 7.65 (d, 1H, J=2.2 Hz), 7.88(dd, 1H, J₁=8.9 Hz, J₂=2.7 Hz). LC-MS (ESI) calcd for C₆H₆N₂O₂S [M+H⁺]171.01. found 193.20 [M+Na⁺].

b) (7-Nitro-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethyl ester

A solution of 2-amino-5-nitro-benzenethiol (Example 8a, 4.1 g, 23.9mmol) in tetrahydrofuran (60 mL) was treated with triethylamine (4.8 g,47.8 mmol) and ethyl chloroacetoacetate (4.3 g, 26.3 mmol). The reactionmixture was stirred at 25° C. for 12 h, concentrated in vacuo, taken upin ethyl acetate, and heated at 80° C. for 3 h. The reaction mixture wasallowed to cool to 25° C., washed with brine solution, dried over sodiumsulfate, and concentrated in vacuo. The resulting brown solid wastriturated with diethyl ether to afford the desired product,(7-nitro-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethyl ester (5.8 g, 20.7mmol, 87% yield) as a yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 1.32 (t,3H, J=7.1 Hz), 3.49 (s, 2H), 4.21 (q, 2H, J=7.0 Hz), 4.89 (s, 1H), 6.91(d, 1H, J=8.7 Hz), 8.00 (dd, 1H, J₁=9.5 Hz, J₂=2.3 Hz), 8.12 (d, 1H,J=3.1 Hz), 10.95 (bs, 1H). LC-MS (ESI) calcd for C₁₂H₁₂N₂O₄S [M+H⁺]281.05. found 281.23 [M+H⁺].

c) (7-Amino-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethyl ester

A solution of (7-nitro-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethylester (Example 8b, 5.8 g, 20.7 mmol) in ethanol (90 mL) was treated withtin (II) chloride and 1.0 M aqueous hydrochloric acid solution (3 mL).The reaction mixture was heated at 100° C. for 3 h. The suspension wasallowed to cool and concentrated. The crude material was suspended inethyl acetate (90 mL) and treated with 6.0 M aqueous sodium hydroxidesolution (90 mL). The resulting precipitate was filtered. The filtercake was thoroughly washed with ethyl acetate, the filtrated was washedwith brine solution, and concentrated in vacuo. The crude oil waspurified by flash chromatography (Merck silica gel 60, 40-63 μm, ethylacetate/hexanes) to afford the desired product,(7-amino-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethyl ester (2.38 g,9.51 mmol, 46% yield) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ 1.21(t, 3H, J=7.1 Hz), 3.30 (s, 2H), 3.43 (bs, 2H), 4.08 (q, 2H, J=7.1 Hz),4.52 (s, 1H), 6.39 (dd, 1H, J₁=8.3 Hz, J₂=2.7 Hz), 6.46 (d, 1H, J=2.3Hz), 6.62 (d, 1H, J=7.6 Hz), 10.38 (bs, 1H). LC-MS (ESI) calcd forC₁₂H₁₄N₂O₂S [M+H⁺] 251.08. found 251.23 [M+H⁺].

d) (7-Methanesulfonylamino-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethylester

A solution of (7-amino-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethylester (Example 8c, 2.38 g, 9.51 mmol) in dichloromethane (80 mL) wascooled to 0° C. and treated with triethylamine (3.1 g, 30.4 mmol)followed by dropwise addition of methanesulfonyl chloride (1.37 g, 9.51mmol). The reaction mixture was stirred at 0° C. for 0.5 h and allowedto warm to 25° C. The reaction mixture was concentrated in vacuo andpurified by flash chromatography (Merck silica gel 60, 40-63 μm, ethylacetate/hexanes) to afford the desired product,(7-methanesulfonylamino-4H-benzo[1,4]thiazin-3-yl)-acetic acid ethylester (2.2 g, 6.7 mmol, 71% yield) as a light tan solid. ¹H NMR (400MHz, CDCl₃) δ 1.31 (t, 3H, J=7.0 Hz), 3.00 (s, 3H), 3.43 (s, 2H), 4.19(quartet, 2H, J=7.1 Hz), 4.73 (s, 1H), 6.28 (s, 1H), 6.85 (d, 1H, J=8.5Hz), 6.99 (dd, 1H, J₁=8.5 Hz, J₂=2.4 Hz), 7.12 (d, 1H, J=2.3 Hz), 10.64(bs, 1H). LC-MS (ESI) calcd for C₁₃H₁₆N₂O₄S [M+H⁺] 329.06. found 329.10[M+H⁺].

e)[7-(Methanesulfonyl-tert-butyloxycarbonyl-amino)-4-tert-butyloxycarbonyl-4H-benzo[1,4]thiazin-3-yl]-aceticacid ethyl ester

A solution of (7-methanesulfonylamino-4H-benzo[1,4]thiazin-3-yl)-aceticacid ethyl ester (Example 8d, 2.2 g, 6.7 mmol) in anhydroustetrahydrofuran (60 mL) was treated with di-tert-butyl-dicarbonate (3.2g, 14.7 mmol) and 4-(dimethylamino)pyridine (0.82 g, 6.7 mmol). Thereaction mixture was stirred at 25° C. under a nitrogen atmosphere for 3h. The solvent was removed in vacuo and the residue was dissolved indichloromethane. The resulting solution was washed with 1.0 M aqueoushydrochloric acid solution, the organic layer was dried over sodiumsulfate, filtered, and concentrated in vacuo. The crude oil was purifiedby flash chromatography (Merck silica gel 60, 40-63 μm, ethylacetate/hexanes) to afford the desired product,[7-(methanesulfonyl-tert-butyloxycarbonyl-amino)-4-tert-butyloxycarbonyl-4H-benzo[1,4]thiazin-3-yl]-aceticacid ethyl ester (1.59 g, 3.01 mmol, 45% yield) as a colorless resin. ¹HNMR (400 MHz, CDCl₃) δ 1.16 (t, 3H, J=7.0 Hz), 1.48 (s, 9H), 1.52 (s,9H), 3.42 (s, 3H), 3.67 (bs, 2H), 4.07 (q, 2H, J=7.3 Hz), 6.26 (s, 1H),7.09 (, 1H, J₁=0.0 Hz, J₂=0.0 Hz), 7.08-7.11 (m, 2H), 7.42 (d, 1H, J=7.8Hz). LC-MS (ESI) calcd for C₂₃H₃₂N₂O₈S₂ [M+H⁺] 529.16. found 429.48[M-Boc⁺].

f)[7-(Methanesulfonyl-tert-butyloxycarbonyl-amino)-4-tert-butyloxycarbonyl-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl]-aceticacid ethyl ester

A solution of[7-(methanesulfonyl-tert-butyloxycarbonyl-amino)-4-tert-butyloxycarbonyl-4H-benzo[1,4]thiazin-3-yl]-aceticacid ethyl ester (Example 8e, 1.59 g, 3.01 mmol) in dichloromethane (50mL) was treated with 3-chloroperoxybenzoic acid (2.23 g, 12.9 mmol). Thereaction mixture was stirred for 12 h at 25° C. A solution of aqueoussodium thiosulfate (2.0 g, 12.9 mmol) was added, and the reaction wasstirred for an additional 0.5 h. The organic layer was separated, washedsequentially with 1.0 M aqueous sodium hydroxide solution, 1.0 M aqueoushydrochloric acid solution, saturated aqueous sodium bicarbonatesolution, and brine, dried over sodium sulfate, filtered, andconcentrated in vacuo. The crude oil was purified by flashchromatography (Merck silica gel 60, 40-63 μm, ethyl acetate/hexanes) toafford the desired product,[7-(methanesulfonyl-tert-butyloxycarbonyl-amino)-4-tert-butyloxycarbonyl-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl]-aceticacid ethyl ester (1.1 g, 1.96 mmol, 64% yield) as a white solid. ¹H NMR(400 MHz, CDCl₃) δ 1.23 (t, 3H, J=7.0 Hz), 1.50 (s, 9H), 1.56 (s, 9H),3.46 (s, 3H), 3.81 (s, 2H), 4.15 (q, 2H, J=7.4 Hz), 6.40 (s, 1H), 7.45(dd, 1H, J₁=9.1 Hz, J₂=2.7 Hz), 7.72 (d, 1H, J=2.3 Hz), 7.91 (d, 1H,J=8.6 Hz). LC-MS (ESI) calcd for C₂₃H₃₂N₂O₈S₂ [M+H⁺] 560.16. found361.18 [M-(2×Boc)⁺].

g)(7-Methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid ethyl ester

A solution of[7-(methanesulfonyl-tert-butyloxycarbonyl-amino)-4-tert-butyloxycarbonyl-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl]-aceticacid ethyl ester (Example 8f, 0.30 g, 0.54 mmol) in 1:1dichloromethane/trifluoroacetic acid was stirred at 25° C. for 2 h. Thereaction mixture was concentrated in vacuo and the residue was dissolvedin ethyl acetate. The solution was washed with saturated aqueous sodiumbicarbonate solution and brine solution. The organic layer was driedover sodium sulfate, filtered, and concentrated in vacuo to afford thedesired product,(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid ethyl ester (0.17 g, 0.47 mmol, 86% yield) as a yellow solid. ¹HNMR (400 MHz, CDCl₃) δ 1.32 (t, 3H, J=6.9 Hz), 3.03 (s, 3H), 4.02 (s,2H), 4.21 (q, 2H, J=7.0 Hz), 5.02 (s, 1H), 6.96 (s, 1H), 7.02 (d, 1H,J=8.4 Hz), 7.53 (dd, 1H, J₁=8.7 Hz, J₂=2.4 Hz), 7.65 (d, 1H, J=2.2 Hz),10.73 (s, 1H). LC-MS (ESI) calcd for C₁₃H₁₆N₂O₆S₂ [M+H⁺] 361.04. found361.18 [M+H⁺].

h)(7-Methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid

A solution of(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid ethyl ester (Example 8g, 0.245 g, 0.680 mmol) in methanol (15 mL)was cooled to 0° C. in an ice-water bath and treated with 2.0 M aqueouslithium hydroxide solution (1.7 mL, 3.40 mmol). The reaction mixture wasallowed to warm to 25° C. and stirred for 1 h. The reaction was pouredinto 0.5 M aqueous hydrochloric acid solution (50 mL) on ice, extractedwith ethyl acetate (3×50 mL), dried over magnesium sulfate, filtered,and concentrated in vacuo to give an orange solid. The crude solid wastriturated with diethyl ether to afford the desired product,(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid (0.175 g, 0.526 mmol, 77% yield) as a light orange solid. LC-MS(ESI) calcd for C₁₁H₁₂N₂O₆S₂ 332.4. found 333.3 [M+H⁺].

i)N-{3-[1-(3,3-Dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-methanesulfonamide

N,N-Dicyclohexylcarbodiimide (0.476 mL of a 1.0 M solution indichloromethane, 0.476 mmol) was added to a solution of(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid (Example 8h, 0.190 g, 0.572 mmol) and1-(3,3-dimethyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester(Example 4c, 0.119 g, 0.475 mmol) in a 3:1 mixture of dichloromethaneand N,N-dimethylformamide (6 mL) at 25° C. The reaction mixture wasstirred at 25° C. for 1 h then was filtered. The filtrate wasconcentrated in vacuo and the residue was dissolved in ethanol (12 mL)at 25° C. A 21% solution of sodium ethoxide in ethanol (0.23 mL, 0.71mmol) was added and the reaction mixture was heated at 80° C. for 5 h.After cooling to 25° C., the mixture was partitioned between 1.0 Maqueous hydrochloric acid solution (150 mL) and ethyl acetate (2×150mL). The organic layers were dried over sodium sulfate, filtered andconcentrated in vacuo. Purification of the residue by flash columnchromatography (Merck silica gel 60, 40-63 μm, 40-100% ethyl acetate inhexanes) afforded a solid which was triturated with diethyl ether toafford the desired product,N-{3-[1-(3,3-dimethyl-butyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-methanesulfonamide(0.101 g, 0.20 mmol, 42% yield) as a yellow solid. ¹H NMR (400 MHz,CDCl₃) δ: 1.07 (9H, s), 1.65-1.72 (2H, m), 3.09 (3H, s), 4.25-4.29 (2H,m), 5.54 (2H, s), 6.43-6.45 (1H, m), 7.01-7.03 (1H, m), 7.08-7.09 (1H,m), 7.30 (1H, d, J=8.5 Hz), 7.39 (1H, bs), 7.61 (1H, dd, J₁=2.3 Hz,J₂=8.6 Hz), 7.73 (1H, d, J=2.4 Hz). LC-MS (ESI) calcd for C₂₂H₂₆N₄O₆S₂506.13. found 507.27 [M+H⁺].

EXAMPLE 9N-{3-[1-(4-Fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

a) 1-(4-Fluoro-benzylamino)-1H-pyrrole-2-carboxylic acid allyl ester

Sodium cyanoborohydride (2.29 g, 36.4 mmol) was added to a solution of1-amino-1H-pyrrole-2-carboxylic acid allyl ester (Example 1b, 3.03 g,18.2 mmol), 4-fluorobenzaldehyde (1.96 mL, 18.3 mmol) and acetic acid (6mL), in methanol (120 mL) at 25° C. The reaction mixture was stirred at25° C. for 18 h, and then was concentrated in vacuo to a volume of about30 mL. The remaining liquid was partitioned between half-saturatedaqueous sodium bicarbonate solution (150 mL) and a 1:1 mixture of ethylacetate and hexanes (2×200 mL). The organic layers were dried oversodium sulfate, filtered and concentrated in vacuo. Purification of theresidue by flash column chromatography (Merck silica gel 60, 40-63 μm,0→40% ethyl acetate in hexanes) afforded the desired product,1-(4-fluoro-benzylamino)-1H-pyrrole-2-carboxylic acid allyl ester (1.87g, 6.8 mmol, 37% yield) as a clear liquid. ¹H NMR (400 MHz, CDCl₃) δ:4.08 (2H, d, J=5.4 Hz), 4.75-4.77 (1H, m), 5.27-5.30 (1H, m), 5.37-5.41(1H, m), 5.95-5.97 (1H, m), 5.98-6.05 (1H, m), 6.58-6.61 (1H, m),6.75-6.76 (1H, m), 6.89-6.91 (1H, m), 6.97-7.01 (2H, m), 7.22-7.25 (2H,m).

b)1-(4-Fluoro-benzyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one

N,N-Dicyclohexylcarbodiimide (4.33 mL of a 1.0 M solution indichloromethane, 4.33 mmol) was added to a solution of(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid (Example 4b, 1.58 g, 4.32 mmol) and1-(4-fluoro-benzylamino)-1H-pyrrole-2-carboxylic acid allyl ester(Example 9a, 1.08 g, 3.94 mmol) in a 4:1 mixture of dichloromethane andN,N-dimethylformamide (25 mL) at 25° C. The reaction mixture was stirredat 25° C. for 2.5 h then was filtered. The filtrate was concentrated invacuo and the residue was dissolved in ethanol (20 mL) at 25° C. A 21%solution of sodium ethoxide in ethanol (8.0 mL, 24.6 mmol) was added andthe reaction mixture was heated at 80° C. for 8 h. After cooling to 25°C., the mixture was partitioned between 1.0 M aqueous hydrochloric acidsolution (150 mL) and ethyl acetate (2×150 mL). The organic layers weredried over sodium sulfate, filtered and concentrated in vacuo to give adark solid. Trituration of this material with methanol afforded a greysolid that was collected by vacuum filtration to afford the desiredproduct,1-(4-fluoro-benzyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one(1.42 g, 2.52 mmol, 64% yield). ¹HNMR (400 MHz, DMSO-d₆) δ: 5.64 (2H,s), 6.58-6.60 (1H, m), 7.01-7.02 (1H, m), 7.14-7.18 (2H, m), 7.42-7.46(2H, m), 7.70-7.70 (1H, m), 8.02-8.04 (1H, m), 8.12-8.12 (1H, m), 13.70(1H, s).

c)N-{3-[1-(4-Fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

1-(4-Fluoro-benzyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one(Example 9b, 0.257 g, 0.455 mmol), potassium phosphate (tribasic) (0.483g, 2.28 mmol), copper (I) iodide (0.022 g, 0.11 mmol), sarcosine (0.024g, 0.273 mmol, and methanesulfonamide (0.433 g, 4.55 mmol) weredissolved in N,N-dimethylformamide (9 mL) at 25° C. The mixture washeated to 100° C. for 6 h, then was allowed to cool to 25° C., dilutedwith ethyl acetate (10 mL), and filtered through Celite. The filtratewas concentrated in vacuo and the residue was purified by flash columnchromatography (Merck silica gel 60, 40-63 μm, 0→10% methanol indichloromethane) to afford a yellow solid. Sequential trituration ofthis material with methanol and diethyl ether afforded the desiredproduct,N-{3-[1-(4-fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide(0.113 g, 0.21 mmol, 47% yield) as a yellow solid. ¹H NMR (400 MHz,DMSO-d₆) δ: 3.08 (3H, s), 5.65 (2H, s), 6.59-6.61 (1H, m), 7.01-7.02(1H, m), 7.14-7.18 (2H, m), 7.42-7.46 (2H, m), 7.54 (1H, dd, J₁=2.3 Hz,J₂=8.6 Hz), 7.62 (1H, d, J=2.5 Hz), 7.66 (1H, d, J=8.9 Hz), 7.71 (1H,s), 10.21 (1H, s), 13.66 (1H, s). LC-MS (ESI) calcd for C₂₂H₁₈FN₅O₆S₂531.07. found 532.10 [M+H⁺].

EXAMPLE 10N-{3-[1-(4-Fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-N-methyl-methanesulfonamide

1-(4-Fluoro-benzyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one (Example 9b,0.269 g, 0.477 mmol), potassium phosphate (tribasic) (0.506 g, 2.38mmol), copper (I) iodide (0.023 g, 0.119 mmol), sarcosine (0.026 g,0.290 mmol, and N-methyl-methanesulfonamide (0.520 g, 4.77 mmol) weredissolved in N,N-dimethylformamide (9 mL) at 25° C. The mixture washeated to 100° C. for 6 h, then was allowed to cool to 25° C., dilutedwith ethyl acetate (10 mL), and filtered through Celite. The filtratewas concentrated in vacuo and the residue was purified by flash columnchromatography (Merck silica gel 60, 40-63 μm, 0→10% methanol indichloromethane) to afford a yellow solid. Sequential trituration ofthis material with methanol and diethyl ether afforded the desiredproduct,N-{3-[1-(4-fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶benzo[1,2,4]thiadiazin-7-yl}-N-methyl-methanesulfonamide (0.169 g, 0.31mmol, 65% yield) as a yellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ: 3.02(3H, s), 3.31 (3H, s), 5.65 (2H, s), 6.59-6.61 (1H, m), 7.01-7.03 (1H,m), 7.14-7.19 (2H, m), 7.42-7.46 (2H, m), 7.68-7.71 (2H, m), 7.75 (1H,dd, J₁=2.4 Hz, J₂=8.7 Hz), 7.90 (1H, d, J=2.2 Hz), 13.72 (1H, s). LC-MS(ESI) calcd for C₂₃H₂₀FN₅O₆S₂ 545.08. found 546.15 [M+H⁺].

EXAMPLE 113-[7-(1,1-Dioxo-tetrahydro-1λ⁶-thiophen-2-yl)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl]-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one

a) Tributyl-(1,1-dioxo-4,5-dihydro-1H-1λ⁶-thiophen-2-yl)-stannane

n-Butyllithium (6.72 mL of a 1.6 M solution in hexanes, 10.7 mmol) wasadded over 5 min to a solution of 2,3-dihydro-thiophene 1,1-dioxide(1.21 g, 10.2 mmol, prepared as described in J. Organomet. Chem., 665,167 (2003)) in tetrahydrofuran (60 mL) at −78° C. The reaction mixturewas stirred at −78° C. for 30 min, then tributyltin chloride (3.04 mL,11.2 mmol) was added over 5 min. After stirring at −78° C. for 45 min,the mixture was warmed to 25° C. and stirred for an additional 45 minthen was concentrated in vacuo. The residue was diluted with chloroform(50 mL) and filtered. The filtrate was partitioned between water (100mL) and a 1:1 mixture of ethyl acetate and hexanes (1×200 mL). Theorganic layer was dried over sodium sulfate, filtered and wasconcentrated in vacuo. Purification of the residue by flash columnchromatography (Merck silica gel 60, 40-63 μm, 20-30% ethyl acetate inhexanes) afforded the desired product,tributyl-(1,1-dioxo-4,5-dihydro-1H-1λ⁶-thiophen-2-yl)-stannane (1.13 g,2.77 mmol, 27% yield) as a yellow solid. ¹H NMR (400 MHz, CDCl₃) δ:0.90-0.95 (9H, m), 1.15-1.21 (6H, m), 1.29-1.40 (8H, m), 1.50-1.67 (6H,m), 2.96-3.00 (1H, m), 3.11-3.14 (1H, m), 6.57 (1H, t, J=3.1 Hz).

b)3-[7-(1,1-Dioxo-4,5-dihydro-1H-1λ⁶-thiophen-2-yl)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl]-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one

1-(4-Fluoro-benzyl)-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶benzo[1,2,4]thiadiazin-3-yl)-pyrrolo[1,2-b]pyridazin-2-one (Example 9b,0.207 g, 0.371 mmol),tributyl-(1,1-dioxo-4,5-dihydro-1H-1λ⁶-thiophen-2-yl)-stannane (Example11a, 0.181 g, 0.442 mmol) and tetrakis(triphenylphosphine)palladium(0)(0.025 g, 0.020 mmol) were dissolved in N,N-dimethylformamide (8 mL) at25° C. The mixture was heated to 90° C. for 24 h, then was allowed tocool to 25° C. and filtered through Celite. The filtrate wasconcentrated in vacuo and the residue was purified by flash columnchromatography (Merck silica gel 60, 40-63 μm, 0→7% methanol indichloromethane) to afford a brown solid. This material wasre-chromatographed (Merck silica gel 60, 40-63 μm, 40-100% ethyl acetatein hexanes, followed by 100% ethyl acetate, followed by 0→7% methanol indichloromethane) to afford the desired product,3-[7-(1,1-dioxo-4,5-dihydro-1H-1λ⁶-thiophen-2-yl)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl]-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one(0.100 g, 0.180 mmol, 48.6% yield). LC-MS (ESI) calcd for C₂₅H₁₉FN₄O₆S₂554.07. found 555.00 [M+H⁺].

c)3-[7-(1,1-Dioxo-tetrahydro-1λ⁶-thiophen-2-yl)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl]-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one

3-[7-(1,1-Dioxo-4,5-dihydro-1H-1λ⁶-thiophen-2-yl)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl]-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one(Example 11b, 0.100 g, 0.180 mmol) was dissolved inN,N-dimethylformamide (15 mL) at 25° C. Palladium on carbon (5%, 0.250g) was added and the atmosphere in the reaction flask replaced withhydrogen from a balloon. After stirring for 1 h under a hydrogenballoon, the mixture was filtered through Celite. The filtrate wasconcentrated in vacuo and the residue was purified by flash columnchromatography (Merck silica gel 60, 40-63 μm, 0→3% methanol indichloromethane) to afford a yellow solid. Trituration of this materialwith diethyl ether afforded the desired product,3-[7-(1,1-dioxo-tetrahydro-1λ⁶-thiophen-2-yl)-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl]-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one(0.028 g, 0.050 mmol, 28% yield). ¹H NMR (400 MHz, DMSO-d₆) δ: 2.08-2.18(1H, m), 2.23-2.29 (1H, m), 2.32-2.43 (1H, m), 3.20-3.28 (1H, m),3.31-3.37 (1H, m), 4.56-4.61 (1H, m), 5.65 (2H, s), 6.60 (2H, d, J=7.0Hz), 6.59-6.61 (1H, m), 7.02-7.03 (1H, m), 7.14-7.18 (2H, m), 7.42-7.46(1H, m), 7.67-7.75 (2H, m), 7.87 (1H, bs), 13.73 (1H, s). LC-MS (ESI)calcd for C₂₅H₂₁FN₄O₆S₂ 556.09. found 557.15 [M+H⁺].

EXAMPLE 123-(1,1-Dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one

3-(1,1-Dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-onewas obtained as a by-product from the reaction described in Example 11b.Column chromatography as described above afforded the desired product,3-(1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(4-fluoro-benzyl)-4-hydroxy-pyrrolo[1,2-b]pyridazin-2-one(0.020 g, 0.046 mmol, 8.1% yield) as a yellow solid. ¹HNMR (400 MHz,DMSO-d₆) δ: 5.65 (2H, s), 6.59 (1H, bs), 7.00-7.01 (1H, m), 7.14-7.18(2H, m), 7.42-7.46 (2H, m), 7.48-7.52 (1H, m), 7.60-7.62 (1H, m),7.69-7.75 (2H, m), 7.87-7.89 (1H, m), 13.69 (1H, s). LC-MS (ESI) calcdfor C₂₁H₁₅FN₄O₄S₂ 438.08. found 439.20 [M+H⁺].

EXAMPLE 13 Cyclopropanesulfonic acid{3-[4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ6-benzo[1,2,4]thiadiazin-7-yl}-amide

a)4-Hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one

4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (Example 1f, 0.218 g, 0.75 mmol) was dissolved inpyridine (1.5 mL) and 2-amino-5-iodo-benzenesulfonamide (Example 4a,0.222 g, 0.75 mmol) was added. The reaction mixture was heated at 120°C. for 16 h, and then 1,8-diazabicyclo[5.4.0]undec-7-ene (0.12 mL, 0.78mmol) was added an heated for another 4 h. The pyridine was removed invacuo to afford the crude desired product. Purification by flash columnchromatography (Merck silica gel 60, 40-63 μm, 5%-10% methanol indichloromethane) afforded the desired product,4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(0.110 g, 0.209 mmol, 28% yield) as a white solid. LC-MS (ESI) calcd forC₁₉H₁₉IN₄O₄S. found 526.02. found 527.20 [M+H⁺].

b) Cyclopropanesulfonic acid{3-[4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ6-benzo[1,2,4]thiadiazin-7-yl}-amide

4-Hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(Example 13a, 0.105 g, 0.199 mmol), potassium triphosphate (0.127 g,0.598 mmol), sarcosine (0.011 g, 0.119 mmol), and copper (I) iodide(0.015 g, 0.080 mmol) were combined. Anhydrous N,N-dimethylformamide (7mL) was added followed by cyclopropanesulfonic acid amide (0.12 g, 1mmol). The solution was degassed while stirring under vacuum and theflask purged with nitrogen. The mixture was stirred at 100° C. for 16 h.Upon cooling, the mixture was diluted with ethyl acetate (200 mL),washed with 1.0 M aqueous hydrochloric acid solution (2×100 mL), driedover magnesium sulfate, filtered and concentrated in vacuo to a solid.Purification by HPLC (Column Luna 5u C18 (2) 100 Å size 50×21.2 mm, 5micron, 40%-95% 0.05% trifluoroacetic acid in acetonitrile/0.05%trifluoroacetic acid in water) afforded the desired product,cyclopropanesulfonic acid{3-[4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-amide(0.052 g, 0.10 mmol, 50% yield) as a pale yellow powder. ¹H NMR (400MHz, DMSO-d₆) δ: 0.97 (10H, m), 1.51 (2H, q, J=7.2 Hz), 1.73 (1H, m),2.71 (1H, m), 4.41 (2H, t, J=7.6 Hz), 6.72 (1H, m), 7.02 (1H, d, J=3.6Hz), 7.58 (1H, m), 7.63 (2H, m), 7.88 (1H, s), 10.12 (1H, bs). LC-MS(ESI) calcd for C₂₂H₂₅N₅O₆S₂. found 519.12. found 520.3 [M+H⁺].

EXAMPLE 14N-{3-[6-Fluoro-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

a) 4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester2-methyl ester

4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester2-methyl ester was prepared as described in Tetrahedron Lett., 44,7809-12 (2003). 4-Oxo-pyrrolidine-1,2-dicarboxylic acid 1-tert-butylester 2-methyl ester (7.12 g, 29.287 mmol) was dissolved indichloromethane (150 mL) and cooled to −78° C. N,N-Diethylaminosulfurtrifluoride (23.58 g, 146.436 mmol) was slowly added to the stirredsolution over a period of 5 min. The reaction was allowed to warm to 25°C. over 16 h. The reaction mixture was poured into ice (200 mL) and thelayers were separated. The organic layer was washed with water andsaturated aqueous sodium bicarbonate solution, dried over sodium sulfateand filtered. The solvent was removed in vacuo to afford the crudedesired product, 4,4-difluoro-pyrrolidine-1,2-dicarboxylic acid1-tert-butyl ester 2-methyl ester (1.90 g, 7.167 mmol, 58.1% yield), asa yellow oil, which was in the next step without further purification.¹H NMR (400 MHz, CDCl₃) δ: 1.44 (9H, s), 2.47 (1H, qd, J₁=13.3 Hz,J₂=4.9 Hz), 2.63-2.78 (1H, m), 3.75-3.96 (5H, m), 4.50 (5H, dm, J₁=40.4Hz, J₂=0.0 Hz), 4.43-4.57 (1H, m).

b) 4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester

4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester2-methyl ester (Example 14a, 7.53 g, 28.403 mmol) was dissolved inacetonitrile (330 mL) and a solution of lithium hydroxide (1.36 g,56.807 mmol) in water (110 mL) was added. After stirring for 16 h at 25°C., the acetonitrile was removed in vacuo and the aqueous phase wasslowly acidified with 1.0 M aqueous hydrochloric acid solution until aprecipitate formed. The product was extracted into ethyl acetate (3×50mL) and the combined organic layers were dried over sodium sulfate andfiltered. The solvent was removed in vacuo to afford the desiredproduct, 4,4-difluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butylester (1.54 g, 6.13 mmol, 95.6% yield) as a brittle, tan solid, whichwas used in the next step without further purification. ¹H NMR (400 MHz,CDCl₃) δ: 1.51 (9H, s), 2.50-2.84 (2H, m), 3.71-3.90 (2H, m), 6.73 (1H,bs).

c) 4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 2-allyl ester1-tert-butyl ester

4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester(Example 14b, 6.77 g, 26.96 mmol) was dissolved in a 5% aqueous sodiumbicarbonate solution (50 mL). Allyl bromide (3.26 g, 26.96 mmol) andtrioctylmethylammonium chloride (“Aliquat® 336”, 10.90 g, 26.97 mmol)were dissolved in dichloromethane (50 mL) and were added to the aqueoussolution. The biphasic reaction mixture was stirred vigorously for 48 hat 25° C. The layers were separated and the aqueous layer was extractedwith dichloromethane (3×70 mL). The combined organic layers were driedover sodium sulfate and filtered. The solvent was removed in vacuo toafford the crude desired product, which was purified by flash columnchromatography (Merck silica gel 60, 40-63 μm, 20% ethyl acetate inhexanes) to afford the desired product,4,4-difluoro-pyrrolidine-1,2-dicarboxylic acid 2-allyl ester1-tert-butyl ester (5.85 g, 20.09 mmol, 74.5% yield) as a clear,slightly yellowish oil. ¹H NMR (400 MHz, CDCl₃) δ: 1.44 (9H, s),2.43-2.54 (1H, m), 2.64-2.80 (1H, m), 3.78-3.94 (2H, m), 4.46-4.73 (3H,m), 5.24-5.37 (2H, m), 5.87-5.96 (1H, m).

d) 4,4-Difluoro-pyrrolidine-2-carboxylic acid allyl estertrifluoroacetic acid salt

4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 2-allyl ester1-tert-butyl ester (Example 14c, 5.85 g, 20.09 mmol) was dissolved in a5% solution of trifluoroacetic acid in dichloromethane and stirred at25° C. for 16 h. The solvent was removed in vacuo and the crude4,4-difluoro-pyrrolidine-2-carboxylic acid allyl ester (6.14 g, 20.09mmol, 100% yield) was obtained as the trifluoroacetic acid salt, whichwas used in the next step without further purification. ¹H NMR (400 MHz,CDCl₃) δ: 2.75-2.86 (1H, m), 2.90-3.02 (1H, m), 3.76-3.93 (2H, m),4.68-4.78 (3H, m), 5.33-5.39 (2H, m), 5.84-5.94 (1H, m).

e) 4-Fluoro-1H-pyrrole-2-carboxylic acid allyl ester

To a solution of 4,4-Difluoro-pyrrolidine-2-carboxylic acid allyl estertrifluoroacetic acid salt (Example 14d, 6.13 g, 20.08 mmol) in anhydroustetrahydrofuran (300 mL) was added manganese (IV) dioxide and thereaction mixture was heated at 80° C. for 4 h. The mixture was filteredover Celite, and was washed with hot and then cold tetrahydrofuran. Thefiltrate was concentrated in vacuo to give a dark orange oil. The oilwas dissolved in ethyl acetate and the organic layer was washed withsaturated aqueous sodium bicarbonate solution. The solvent was removedin vacuo to give an orange oil, which was purified by flash columnchromatography (Merck silica gel 60, 40-63 μm, 30% ethyl acetate inhexanes) to afford the desired product, 4-fluoro-1H-pyrrole-2-carboxylicacid allyl ester (3.01 g, 17.80 mmol, 88.7% yield) as a yellow oil. ¹HNMR (400 MHz, CDCl₃) δ: 4.77 (2H, d, J=5.7 Hz), 5.29 (1H, d, J=10.2 Hz),5.38 (1H, d, J=15.9 Hz), 5.94-6.04 (1H, m), 6.64-6.65 (1H, m), 6.72-6.74(1H, m), 8.91 (1H, bs).

f) 1-Amino-4-fluoro-1H-pyrrole-2-carboxylic acid allyl ester

1-Amino-4-fluoro-1H-pyrrole-2-carboxylic acid allyl ester was preparedfollowing the N-amination procedure described in Tetrahedron Lett., 47,5341-43 (2006). 4-Fluoro-1H-pyrrole-2-carboxylic acid allyl ester(Example 14e, 2.49 g, 14.74 mmol) was mixed together with solid ammoniumchloride (4.81 g, 90.75 mmol), 30% aqueous sodium hydroxide solution(42.4 mL), 29.56% aqueous ammonium hydroxide solution (13.71 mL) andtrioctylmethylammonium chloride (“Aliquat® 336”, 0.166 g, 0.411 mmol) inmethyl tert-butyl ether (50 mL). Under vigorous stirring, a 6.15%aqueous bleach solution (“Chlorox”, 146 mL) was slowly added viaaddition funnel upon which the color of the solution turned orange.After stirring for 2 h at 25° C., the layers were separated and theaqueous layer was extracted with methyl tert-butyl ether (2×10 mL). Thecombined organic layers were washed with a saturated sodium thiosulfatesolution (50 mL) and the organic layer was dried over sodium sulfate andfiltered. The solvent was removed in vacuo and the crude product waspurified by flash column chromatography (Merck silica gel 60, 40-63 μm,20% ethyl acetate in hexanes) to afford the desired product,1-amino-4-fluoro-1H-pyrrole-2-carboxylic acid allyl ester (2.02 g, 10.99mmol, 62.1% yield). ¹H NMR (400 MHz, CDCl₃) δ: 4.73 (2H, d, J=5.5 Hz),5.26-5.29 (1H, m), 5.34-5.40 (1H, m), 5.52 (2H, bs), 5.93-6.02 (1H, m),6.49-6.53 (1H, m), 6.78-6.80 (1H, m).

g) 4-Fluoro-1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid allylester

To a solution of 1-amino-4-fluoro-1H-pyrrole-2-carboxylic acid allylester (Example 14f, 0.5 g, 2.717 mmol) in methanol (20 mL) were addedisovaleraldehyde (0.257 g, 2.988 mmol) and sodium cyanoborohydride(0.256 g, 4.075 mmol). The mixture was stirred for 20 h at 25° C. Thesolvent was removed in vacuo and the crude product was purified by flashcolumn chromatography (Merck silica gel 60, 40-63 μm, 20% ethyl acetatein hexanes) to afford the desired product,4-fluoro-1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid allylester (0.264 g, 1.039 mmol, 38.2% yield) as a yellow oil. ¹HNMR (400MHz, CDCl₃) δ: 0.91 (3H, s), 0.93 (3H, s), 1.38-1.45 (2H, m), 1.63-1.80(1H, m), 3.00-3.05 (2H, m), 4.74-4.76 (1H, m), 5.29 (1H, d, J=10.4 Hz),5.38 (1H, d, J=18.8 Hz), 5.94-6.03 (1H, m), 6.52-6.56 (1H, m), 6.79-6.81(1H, m).

h)1-[(2-Methoxycarbonyl-acetyl)-(3-methyl-butyl)-amino]-4-fluoro-1H-pyrrole-2-carboxylicacid allyl ester

4-Fluoro-1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid allylester (Example 14 g, 0.24 g, 0.944 mmol) was dissolved in anhydrous1,4-dioxane (10 mL) and methyl malonyl chloride was added under anitrogen atmosphere. The reaction mixture was heated to 100° C. for 1 h.Upon cooling to 25° C., saturated aqueous sodium bicarbonate solutionwas added and the product was extracted with 50% ethyl acetate/hexanes.The combined organic layers were dried over sodium sulfate, filtered andconcentrated in vacuo to afford the crude desired product,1-[(2-ethoxycarbonyl-acetyl)-(3-methyl-butyl)-amino]-4-fluoro-1H-pyrrole-2-carboxylicacid allyl ester (0.335 g, 0.944 mmol, 100% yield) as a pale yellow oil,which was used in the next step without further purification. ¹H NMR(400 MHz, CDCl₃) δ: 0.90 (3H, d, J=4.6 Hz), 0.92 (3H, d, J=5.2 Hz),1.37-1.46 (1H, m), 1.54-1.64 (1H, m), 1.69-1.78 (1H, m), 3.13 (2H, d,J=3.1 Hz), 3.70 (3H, s), 4.16-4.26 (2H, m), 4.73 (2H, d, J=5.5 Hz),5.28-5.31 (1H, m), 5.37 (1H, dd, J₁=17.2 Hz, J₂=1.6 Hz), 5.91-6.01 (1H,m), 6.69-6.76 (2H, m).

i)6-Fluoro-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester

To a solution of1-[(2-ethoxycarbonyl-acetyl)-(3-methyl-butyl)-amino]-4-fluoro-1H-pyrrole-2-carboxylicacid allyl ester (Example 14h, 0.318 g, 0.898 mmol) in ethanol (10 mL)was added a 21% solution of sodium ethoxide in ethanol (0.728 g, 2.245mmol) and the mixture was heated at 40° C. for 16 h. The solvent wasremoved in vacuo and the residue was purified by flash columnchromatography (Merck silica gel 60, 40-63 μm, 20% ethyl acetate inhexanes, then 10% methanol in dichloromethane) to afford the desiredproduct,6-fluoro-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (0.137 g, 0.441 mmol, 49.1% yield) as a yellow oil.¹HNMR (400 MHz, CDCl₃) δ: 0.99 (3H, s), 1.00 (3H, s), 1.44 (3H, t, J=7.0Hz), 1.58-1.63 (2H, m), 1.67-1.75 (1H, m), 4.18-4.22 (2H, m), 4.44 (2H,quartet, J=7.1 Hz), 6.55 (1H, m), 7.04 (1H, m).

j) 6-Fluoro-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one

6-Fluoro-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (Example 141, 136.7 mg, 0.441 mmol) and2-amino-5-iodo-benzenesulfonamide (Example 4a, 131.3 mg, 0.441 mmol)were mixed in anhydrous pyridine (2 mL) and heated at 120° C. for 3 h.1,8-Diazabicyclo[5.4.0]undec-7-ene (200 μL) was added and the mixturewas heated at 120° C. for 16 h. Purification by flash columnchromatography (Merck silica gel 60, 40-63 μm, 20% ethyl acetate inhexanes) afforded the desired product,6-fluoro-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(0.047 g, 0.086 mmol, 19.5% yield) as a dark purple solid. LC-MS (ESI)calcd for C₁₉H₁₈FIN₄O₄S 544.01. found 544.97 [M+H⁺].

k)N-{3-[6-Fluoro-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

6-Fluoro-4-hydroxy-3-(7-iodo-1,1-dioxo-1,4-dihydro-1λ⁶benzo[1,2,4]thiadiazin-3-yl)-1-(3-methyl-butyl)-pyrrolo[1,2-b]pyridazin-2-one(Example 14j, 0.047 g, 0.086 mmol), potassium triphosphate (0.055 g,0.258 mmol), sarcosine (0.0046 g, 0.0516 mmol), and copper (J) iodide(0.0066 g, 0.0344 mmol) were combined. Anhydrous N,N-dimethylformamide(3 mL) was added followed by methanesulfonamide (0.0245 g, 0.258 mmol).The flask was purged with nitrogen and the mixture was stirred at 100°C. for 16 h. Upon cooling, the mixture was filtered over Celite, washedwith ethyl acetate and the solvent was removed in vacuo. Purification bypreparative HPLC (Column Luna 5μ C18 (2) 100 Å size 150×21.2 mm, 5micron, 40%-95% in 11 min 25 mL/min flow rate, 0.05% trifluoroaceticacid in acetonitrile/0.05% trifluoroacetic acid in water) afforded thedesired product,N-{3-[6-fluoro-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide(0.0068 g, 0.0133 mmol, 15.4% yield) as a solid. ¹H NMR (400 MHz,DMSO-d₆) δ: 0.96 (3H, s), 0.97 (3H, s), 1.53-1.59 (2H, m), 1.66-1.76(1H, m), 3.07 (3H, s), 4.32 (2H, t, J=7.5 Hz), 6.83 (1H, bs), 7.51-7.63(3H, m), 8.06 (1H, bs), 10.17 (1H, bs). LC-MS (ESI) calcd forC₂₀H₂₂FN₅O₆S₂ 511.10. found 512.3 [M+H⁺].

EXAMPLE 15N-{3-[6-Cyano-4-hydroxy-1-(3-methyl-butyl)-2-oxo-[1,2-dihydro-pyrrolo[1,2-b]]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

a) 4-Cyano-1H-pyrrole-2-carboxylic acid methyl ester

4-Cyano-1H-pyrrole-2-carboxylic acid methyl ester was prepared asdescribed in Can. J. Chem., 59, 2673-76 (1981). 1H-Pyrrole-2-carboxylicacid methyl ester (2.00 g, 16.00 mmol) was dissolved in acetonitrile (5mL) and the solution was cooled to −20° C. Chlorosulfonylisocyanate(3.40 g, 24.00 mmol) was dissolved in acetonitrile (5 mL) and addeddropwise via syringe over a period of 5 min to the above solution. Thesolution was allowed to warm to 25° C. and was stirred for 20 h. Thesolution was cooled back to 0° C., N,N-dimethylformamide (2 mL) wasadded and the solution was heated to 50° C. for 15 min. The reactionmixture was poured into ice and was extracted with chloroform, washedwith saturated aqueous sodium bicarbonate solution, dried over sodiumsulfate, filtered and concentrated in vacuo. Purification by flashcolumn chromatography (Merck silica gel 60, 40-63 μm, 40% ethyl acetatein hexanes) afforded the desired product,4-cyano-1H-pyrrole-2-carboxylic acid methyl ester (1.09 g, 7.265 mmol,45.4% yield) as an off-white solid. ¹H NMR (400 MHz, CDCl₃) δ: 3.91 (3H,s), 7.12 (1H, t, J=2.0 Hz), 7.40-7.41 (1H, m), 9.60 (1H, bs). FT-IR(ATR) ν_(max) (neat): 2228, 1691 cm⁻¹.

b) 1-Amino-4-cyano-1H-pyrrole-2-carboxylic acid methyl ester

Solid ammonium chloride (5.8 g, 109.4 mmol) was suspended in diethylether (300 mL) and the suspension was cooled to −5° C. To this wereadded 29.56% aqueous ammonium hydroxide solution (16 mL) and 6.15%aqueous bleach solution (“Chlorox”, 240 mL) over a period of 15 min. Themixture was stirred for 30 min at −5° C. and then the layers wereseparated. The organic layer was washed with brine, filtered over sodiumsulfate and stored over solid calcium chloride at −5° C.4-Cyano-1H-pyrrole-2-carboxylic acid methyl ester (Example 15a, 1.09 g,7.265 mmol) was dissolved in N,N-dimethylformamide (30 mL) and a 60%dispersion of sodium hydride in mineral oil (0.378 g, 9.445 mmol) wasadded. After stirring for 1 h at 25° C., the above ˜0.36 M solution ofmonochloramine in ether (26 mL, 9.445 mmol) was added and stirred for 2h at 25° C. The reaction was quenched with saturated aqueous sodiumthiosulfate solution followed by water. The layers were separated andthe aqueous layer was extracted with diethyl ether. The combined organiclayers were dried over sodium sulfate, filtered and concentrated invacuo to afford the crude desired product,1-amino-4-cyano-1H-pyrrole-2-carboxylic acid methyl ester, which wasused in the next step without further purification. ¹H NMR (400 MHz,CDCl₃) δ: 3.88 (3H, s), 5.67 (2H, bs), 7.07 (1H, d, J=1.7 Hz), 7.37 (1H,d, J=1.7 Hz).

c) 4-Cyano-1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid methylester

The crude 1-amino-4-cyano-1H-pyrrole-2-carboxylic acid methyl ester(Example 15b, 0.60 g, 3.635 mmol) and isovaleraldehyde (0.313 g, 3.635mmol) were dissolved in isopropanol (15 mL) and heated at 50° C. for 72h. The solvent was removed in vacuo to afford the imine as a yellowishoil. The intermediate was dissolved in methanol (20 mL) and sodiumborohydride (0.206 g, 5.453 mmol) was added. After stirring at 25° C.for 30 min, the reaction was quenched with 1.0 M sodium hydroxidesolution. The aqueous layer was extracted with ethyl acetate and thecombined organic layers were dried over sodium sulfate, filtered andconcentrated in vacuo. Purification by flash column chromatography(Merck silica gel 60, 40-63 μm, 40% ethyl acetate in hexanes) affordedthe desired product,4-cyano-1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylic acid methylester (0.604 g, 2.591 mmol, 71.3% yield) as a yellowish oil. ¹H NMR (400MHz, CDCl₃) δ: 0.92 (3H, s), 0.94 (3H, s), 1.37-1.43 (2H, m), 1.64-1.74(1H, m), 2.99-3.04 (2H, m), 3.88 (3H, s), 6.40 (1H, t, J=6.3 Hz), 7.09(1H, d, J=1.5 Hz), 7.36 (1H, d, J=2.2 Hz). LC-MS (ESI) calcd forC₁₂H₁₇N₃O₂ 235.13. found 236.3 [M+H⁺].

d)4-Cyano-1-[(2-ethoxycarbonyl-acetyl)-(3-methyl-butyl)-amino]-1H-pyrrole-2-carboxylicacid methyl ester

To a solution of 4-cyano-1-(3-methyl-butylamino)-1H-pyrrole-2-carboxylicacid methyl ester (Example 15c, 0.600 g, 2.552 mmol) in anhydrous1,4-dioxane (25 mL) was added methyl malonyl chloride (0.383 g, 2.807mmol) and the reaction mixture was heated at 100° C. for 3 h. Uponcooling, the reaction was quenched with saturated aqueous sodiumbicarbonate solution and was extracted with 50% ethyl acetate/hexanes(3×30 mL). The combined organic layers were dried over sodium sulfate,filtered and concentrated in vacuo to afford the crude desired product,4-cyano-1-[(2-ethoxycarbonyl-acetyl)-(3-methyl-butyl)-amino]-1H-pyrrole-2-carboxylicacid methyl ester as a yellowish oil, which was used in the next stepwithout further purification. LC-MS (ESI) calcd for C₁₆H₂₁N₃O₅ 335.15.found 336.4 [M+H⁺].

e)6-Cyano-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester

To a solution of crude4-cyano-1-[(2-ethoxycarbonyl-acetyl)-(3-methyl-butyl)-amino]-1H-pyrrole-2-carboxylicacid methyl ester (Example 15d, 2.552 mmol) in ethanol (30 mL) was addeda 21% solution of sodium ethoxide in ethanol (2.07 g, 6.380 mmol) andthe mixture was heated at 40° C. for 16 h. Upon cooling, the mixture wasquenched with 1.0 M aqueous hydrochloric acid solution and brine. Theaqueous mixture was extracted with ethyl acetate and the combinedorganic layers were dried over sodium sulfate, filtered and concentratedin vacuo to afford the crude desired product,6-cyano-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester as a yellow solid, which was used in the next stepwithout further purification. LC-MS (ESI) calcd for C₁₆H₁₉N₃O₄ 317.14.found 318.3 [M+H⁺]. FT-IR (ATR) ν_(max) (neat): 2231, 1642, 1610 cm⁻¹.

f)N-{3-[6-Cyano-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

A solution of6-cyano-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazine-3-carboxylicacid ethyl ester (Example 15e, 0.25 g, 0.788 mmol) and2-amino-5-methanesulfonylamino-benzenesulfonamide (Example 3d, 0.209 g,0.788 mmol) in pyridine (4 mL) was heated to 120° C. for 3 h.1,8-Diazabicyclo[5.4.0]undec-7-ene (200 μL) was added and the mixturewas heated at 120° C. for 16 h. The reaction mixture was passed througha plug of silica gel and eluted with 50%-100% ethyl acetate in hexanes.The solvents were removed in vacuo and purification by preparative HPLC(Column Luna 5μ C18 (2) 100 Å size 150×21.2 mm, 5 micron, 40%-95% in 11min 25 mL/min flow rate, 0.05% trifluoroacetic acid inacetonitrile/0.05% trifluoroacetic acid in water) afforded the desiredproduct,N-{3-[6-cyano-4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide(0.0275 g, 0.0531 mmol, 6.7% yield). ¹H NMR (400 MHz, DMSO-d₆) δ: 0.94(3H, s), 0.96 (3H, s), 1.17-1.23 (2H, m), 1.51-1.57 (2H, m), 1.65-1.75(1H, m), 5.74 (1H, s), 3.05 (3H, s), 7.40 (1H, s), 7.49-7.57 (3H, m),8.51 (1H, s), 10.12 (1H, s), 13.75 (1H, s). LC-MS (ESI) calcd forC₂₁H₂₂N₆O₆S₂ 518.10. found 519.4 [M+H⁺].

EXAMPLE 16N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-methanesulfonamide

a)1-[[2-(7-Methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-acetyl]-(3-methyl-butyl)-amino]-1H-pyrrole-2-carboxylicacid allyl ester

(7-Methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-aceticacid (Example 81, 0.1 g, 0.3 mmol) was dissolved in anhydrousN,N-dimethylformamide (3 mL).1-(3-Methyl-butylamino)-1H-pyrrole-2-carboxylic acid allyl ester(Example 1c, 0.07 g, 0.3 mmol) was added followed by1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.06 g,0.315 mmol). Then N-methylmorpholine (0.07 mL, 0.63 mmol) was added intothe above reaction mixture. The mixture was stirred at 25° C. for 4 h.The solution was poured into 1.0 M aqueous hydrochloric acid solution(50 mL). The aqueous layer was extracted with ethyl acetate (2×50 mL).The organic phase was dried over sodium sulfate, filtered andconcentrated in vacuo to afford the crude desired product,1-[[2-(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-acetyl]-(3-methyl-butyl)-amino]-1H-pyrrole-2-carboxylicacid allyl ester (0.3 mmol) as a yellow oil, which was used in the nextstep without further purification. LC-MS (ESI) calcd for C₂₄H₃₀N₄O₇S₂550.16. found 551.6 [M+H⁺].

b)N-{3-[4-Hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-methanesulfonamide

Crude1-[[2-(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-3-yl)-acetyl]-(3-methyl-butyl)-amino]-1H-pyrrole-2-carboxylicacid allyl ester (Example 16a, 0.3 mmol) was dissolved in ethanol (3mL). A 21% solution of sodium ethoxide in ethanol (0.448 mL, 1.2 mmol)was added into the above solution. The mixture was stirred at 60° C. for4 h. Upon cooling to 25° C., the mixture was poured into 1.0 M aqueoushydrochloric acid solution (50 mL). The aqueous layer was extracted withethyl acetate (2×50 mL). The organic phase was dried over sodiumsulfate, filtered and concentrated in vacuo to afford a yellow solid.Purification by flash column chromatography (Teledyne Isco RediSep; 20%ethyl acetate in hexanes to 100% ethyl acetate in hexanes) afforded thedesired product,N-{3-[4-hydroxy-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,4]thiazin-7-yl}-methanesulfonamide(20 mg, 0.04 mmol, 13% yield over two steps) as a yellow solid. ¹H NMR(400 MHz, CDCl₃) δ: 1.05 (6H, d, J=6.6 Hz), 1.64-1.81 (3H, m), 3.11 (3H,s), 4.24-4.31 (2H, m), 5.53 (1H, s), 6.41-6.46 (1H, m), 6.97-7.10 (3H,m), 7.30-7.33 (1H, m), 7.60-7.64 (1H, m), 7.70-7.72 (1H, m). LC-MS (ESI)calcd for C₂₁H₂₄N₄O₆S₂ 492.11. found 493.3 [M+H⁺].

EXAMPLE 17N-{3-[1-(3-Chloro-4-fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

a) 2-Chloro-5-nitrobenzenesulfonamide

To a solution of thionyl chloride (11 mL) and2-chloro-5-nitro-benzenesulfonic acid (4.78 g, 20.1 mmol) was addedN,N-dimethylformamide (0.92 μL) and the reaction mixture was heated toreflux for 4 h. Upon cooling, the reaction mixture was azeotroped withtoluene (2-3×). The sulfonyl chloride was dissolved in a minimal amountof toluene and then added to a mixture of concentrated aqueous ammoniumhydroxide solution (25 mL) and tetrahydrofuran (25 mL) at −10° C. Afterstirring for 2 h the reaction was quenched by adding a 6.0 M aqueoushydrochloric acid solution until pH 4 was reached. The layers wereseparated and the organic layer was concentrated in vacuo to a slurry.Pentane was added and the product was isolated by vacuum filtration toafford the desired product, 2-chloro-5-nitrobenzenesulfonamide (2.0 g,8.48 mmol, 42.4% yield) as a solid.

Alternatively, 2-chloro-5-nitrobenzenesulfonamide can be prepared asfollows:

4-Chloronitrobenzene (10 g, 63.5 mmol) was charged into a flask,followed by addition of chlorosulfonic acid (21.1 mL, 317 mmol), andheated at 120° C. for 100 h. The reaction mixture was quenched bypouring it into ice (300 mL) containing 8.0 N aqueous ammonium hydroxidesolution (200 mL), and the mixture was allowed to stir at 25° C. for 18h. The desired product was extracted with ethyl acetate (400 mL) andfiltered through Merck silica gel 60, 40-63 μm and concentrated invacuo. The crude product was slurried in toluene (70 mL) at 70° C. for 2h before filtering to afford the desired product,2-chloro-5-nitro-benzenesulfonamide (4.75 g, 20.1 mmol, 29% yield) as adark, brown solid. ¹H NMR (400 MHz, DMSO-d₆) δ: 7.94 (d, 1H, J=8.8 Hz),7.97 (bs, 2H), 8.40 (dd, 1H, J₁=8.6 Hz, J₂=3.1 Hz), 8.64 (d, 1H, J=3.1Hz).

b) 2-Amino-5-nitrobenzenesulfonamide

A mixture of 2-chloro-5-nitrobenzenesulfonamide (Example 17a, 0.88 g,3.72 mmol), ammonium carbonate (0.88 g, 9.16 mmol), and copper (II)sulfate (0.175 g, 1.10 mmol) in concentrated aqueous ammonium hydroxidesolution (4.4 mL) was heated for 4 h at 120° C. in a pressure reactionvessel. The mixture was allowed to cool to 25° C. and the resultingsolid was collected by vacuum filtration, washed with water and dried toafford the desired product, 2-amino-5-nitrobenzenesulfonamide (0.295 g,1.36 mmol, 36.5% yield) as a tan solid.

Alternatively, 2-amino-5-nitrobenzenesulfonamide can be prepared asfollows: To a suspension of 4-nitroaniline-2-sulfonic acid sodium salt(20.00 g, 83.27 mmol) in sulfolane (83 mL) was slowly added phosphorousoxychloride (23 mL, 249.82 mmol) at 25° C. The mixture was heated at120° C. for 3.5 h, allowed to cool to 25° C. and diluted withdichloromethane (300 mL). The mixture was filtered and the precipitatewas washed with dichloromethane (200 mL). The filtrate was treated withammonia gas for 10 minutes while cooling in an ice bath and then stirredat 25° C. for 5 minutes. The yellow solid was collected by vacuumfiltration and the precipitate was further washed with dichloromethane(300 mL, then 200 mL), cold water (2×150 mL) and dried in vacuo for 16 hat 60° C. to afford the desired product,2-amino-5-nitrobenzenesulfonamide (8.06 g, 37.14 mmol, 44% yield) as ayellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ: 6.89 (d, J=9.3 Hz, 1H), 7.12(bs, 2H), 7.57 (bs, 2H), 8.07 (dd, J₁=9.0 Hz, J₂=2.6 Hz, 1H), 8.43 (d,J=3.0 Hz, 1H).

Alternatively, 2-amino-5-nitrobenzenesulfonamide can be prepared asfollows: To a suspension of 4-nitroaniline-2-sulfonic acid sodium salt(20.00 g, 83.27 mmol) in sulfolane (83 mL) was slowly added phosphorousoxychloride (23 mL, 249.82 mmol) at 25° C. The mixture was heated at120° C. for 3.5 h, allowed to cool to 25° C. and diluted with toluene(300 mL). The mixture was filtered and the precipitate was washed withtoluene (200 mL). The filtrate was treated with ammonia gas for 10minutes while cooling in an ice bath and then stirred at 25° C. for 5minutes. The yellow solid was collected by vacuum filtration and theprecipitate was further washed with toluene (300 mL, then 200 mL), coldwater (2×150 mL) and dried in vacuo for 16 h at 60° C. to afford thedesired product, 2-amino-5-nitrobenzenesulfonamide (7.39 g, 34.05 mmol,41% yield) as a yellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ: 6.89 (d,J=9.3 Hz, 1H), 7.12 (bs, 2H), 7.57 (bs, 2H), 8.07 (dd, J₁=9.0 Hz, J₂=2.6Hz, 1H), 8.43 (d, J=3.0 Hz, 1H).

Alternatively, 2-amino-5-nitrobenzenesulfonamide can be prepared asfollows: To a suspension of 2-amino-5-nitro-benzenesulfonic acid (3.00g, 13.75 mmol) in sulfolane (10 mL) was slowly added phosphorousoxychloride (3.43 mL, 37.47 mmol) at 25° C. The mixture was heated at120° C. for 3.5 h, allowed to cool to 25° C. and diluted withdichloromethane (50 mL). The mixture was filtered and the precipitatewas washed with dichloromethane (50 mL). The filtrate was treated withammonia gas for 10 minutes while cooling in an ice bath and then stirredat 25° C. for 5 minutes. The yellow solid was collected by vacuumfiltration and the precipitate was further washed with dichloromethane(2×50 mL), cold water (2×50 mL) and dried in vacuo for 16 h at 60° C. toafford the desired product, 2-amino-5-nitrobenzenesulfonamide (1.46 g,6.73 mmol, 49% yield) as a brown solid. ¹H NMR (400 MHz, DMSO-d₆) δ:6.89 (d, J=9.1 Hz, 1H), 7.19 (bs, 2H), 7.37 (bs, 2H), 8.07 (dd, J₁=8.9Hz, J₂=2.3 Hz, 1H), 8.43 (d, J=3.0 Hz, 1H).

Alternatively, 2-amino-5-nitrobenzenesulfonamide can be prepared asfollows: To a suspension of 2-amino-5-nitro-benzenesulfonic acid (3.00g, 13.75 mmol) in sulfolane (10 mL) was slowly added phosphorousoxychloride (3.43 mL, 37.47 mmol) at 25° C. The mixture was heated at120° C. for 3.5 h, allowed to cool to 25° C. and slowly poured intoaqueous ammonium hydroxide solution (30 mL) at 25° C. The pH of thesolution was adjusted to ca. 6-7 upon which a solid precipitated. Thesolid was collected by vacuum filtration and the precipitate was washedwater (100 mL) and dried in vacuo for 16 h at 60° C. to afford thedesired product, 2-amino-5-nitrobenzenesulfonamide (1.87 g, 8.62 mmol,63% yield) as a yellow-brown solid. ¹HNMR (400 MHz, DMSO-d₆) δ: 6.89 (d,J=9.1 Hz, 1H), 7.19 (bs, 2H), 7.37 (bs, 2H), 8.07 (dd, J₁=8.9 Hz, J₂=2.3Hz, 1H), 8.43 (d, J=3.0 Hz, 1H).

c) 2,5-Diaminobenzenesulfonamide

A mixture of 2-amino-5-nitrobenzenesulfonamide (Example 17b, 10 g, 46.08mmol), 10% palladium on charcoal (˜1 g) in tetrahydrofuran (250 mL) washydrogenated for 26 h at 25° C. under 1 atmosphere of hydrogen gas viaballoon. The mixture was then filtered through Celite, washed withtetrahydrofuran, and the solvent removed in vacuo to afford the desiredproduct. The catalyst/Celite mixture was slurried in methanol (400 mL)for 16 h, filtered and the solvent was removed in vacuo to afford asecond batch of the desired product, 2,5-diaminobenzenesulfonamide(combined: 7.79 g, 41.65 mmol, 90.4% yield) as a light-brown solid. ¹HNMR (400 MHz, DMSO-d₆) δ: 4.54 (2H, bs), 4.98 (2H, bs), 6.55-6.60 (2H,m), 6.87 (1H, d, J=2.2 Hz), 6.99 (2H, bs). LC-MS (ESI) calcd forC₆H₉N₃O₂S 187.04. found 188.3 [M+H⁺].

Alternatively, 2,5-diaminobenzenesulfonamide can be prepared as follows:

i) 2-Benzylamino-5-nitro-benzenesulfonamide

A solution of 2-chloro-5-nitro-benzenesulfonamide (20 g, 84.52 mmol) inacetonitrile (169 mL) was treated with benzylamine (13.85 mL, 126.78mmol), diisopropyl ethylamine (29.44 mL, 169.04 mmol) and stirred for 16h at 55° C. The reaction was cooled to 25° C., poured into water (1.0 L)then placed in an ice bath while stirring. After 4 h a precipitate wasfiltered off and washed with the mother liquor to afford the desiredproduct, 2-benzylamino-5-nitro-benzenesulfonamide (21.65 g, 70.45 mmol,83.3% yield) as a yellow solid. ¹H NMR (400 MHz, DMSO-d₆) 6:4.64 (2H, d,J=4.6 Hz), 6.81 (1H, d, J=9.4 Hz), 7.23-7.44 (6H, m), 7.77 (2H, bs),8.11 (1H, dd, J₁=9.4 Hz, J₂=2.3 Hz), 8.49 (1H, d, J=3.1 Hz). LC-MS (ESI)calcd for C₁₃H₁₃N₃O₄S 307.06. found 308.2 [M+H⁺] (100%), 615.2 [2M+H⁺](81%).

ii) 2,5-Diamino-benzenesulfonamide

A mixture of 2-benzylamino-5-nitro-benzenesulfonamide (Example 17ci, 15g, 48.81 mmol) and 5% palladium on activated carbon powder (wet,nominally 50% water, 6 g) in methanol (500 mL) was heated to 55° C. Themixture was degassed while stirring and the flask was charged withhydrogen gas via balloon. After stirring for 16 h under 1 atmosphere ofhydrogen gas, the reaction was filtered through Celite and concentratedin vacuo to afford the desired product, 2,5-diamino-benzenesulfonamide(8.55 g, 45.67 mmol, 93.6% yield) as a tan solid. ¹H NMR (400 MHz,DMSO-d₆) δ: 4.56 (2H, bs), 4.98 (2H, bs), 6.58-6.59 (2H, m), 6.87 (1H,d, J=1.6 Hz), 7.00 (2H, s). LC-MS (ESI) calcd for C₆H₉N₃O₂S 187.04.found 188.2 [M+H⁺] (100%).

d) 2-Amino-5-methanesulfonylamino-benzenesulfonamide

2,5-Diaminobenzenesulfonamide (Example 17c, 11.16 g, 59.61 mmol) wasdissolved in acetonitrile (300 mL) and pyridine (7.07 g, 89.41 mmol) wasadded. Methanesulfonyl chloride (7.17 g, 62.59 mmol) was added dropwiseover a period of 10 min and the reaction mixture was stirred for 16 h at25° C. after which time a precipitate had formed. Most of theacetonitrile was removed in vacuo and water (200 mL) was added to afforda clear solution. The product slowly started to precipitate and themixture was placed in an ice bath for 3 h. The precipitate was collectedby vacuum filtration and dried under high vacuum to afford the desiredproduct, 2-amino-5-methanesulfonylamino-benzenesulfonamide (also made inExamples 3d and 3d′) (11.1 g, 41.84 mmol, 70.2% yield) as a brown solid.¹H NMR (400 MHz, CD₃OD) δ: 2.89 (3H, s), 6.82 (1H, d, J=8.5 Hz), 7.20(1H, dd, J₁=8.5 Hz, J₂=2.5 Hz), 7.58 (1H, d, J=2.5 Hz). LC-MS (ESI)calcd for C₇H₁₁N₃O₄S₂ 265.02. found 266.0 [M+H⁺].

e) N-(4-Methanesulfonylamino-2-sulfamoyl-phenyl)-malonamic acid ethylester

2-Amino-5-methanesulfonylamino-benzenesulfonamide (Example 17d, 23.27 g,87.81 mmol) was dissolved in N,N-dimethylacetamide (100 mL) and diethylether (100 mL). Ethyl 3-chloro-3-oxo-propionate (13.88 g, 92.20 mmol)was added and the reaction mixture was stirred at 25° C. for 1 h. Thereaction mixture was diluted with ethyl acetate (400 mL) and wasextracted with water (400 mL). The aqueous layer was back-extracted withethyl acetate (2×200 mL). The combined organic layers were dried oversodium sulfate, filtered and most of the solvent was removed in vacuo toa volume of ˜100 mL. To the stirred solution was added hexanes (˜100 mL)upon which a precipitate formed. The precipitate was collected by vacuumfiltration, washed with hexanes and dried under high vacuum to affordthe analytically pure product,N-(4-methanesulfonylamino-2-sulfamoyl-phenyl)-malonamic acid ethyl ester(31.22 g, 85.53 mmol, 97.4% yield) as a light-brown solid. ¹H NMR (400MHz, CD₃OD) δ: 1.31 (3H, t, J=7.0 Hz), 3.00 (3H, s), 3.59 (2H, s), 4.25(2H, quartet, J=6.9 Hz), 7.42-7.45 (1H, m), 7.86 (1H, m), 7.92 (1H, d,J=8.8 Hz).

Alternatively, N-(4-methanesulfonylamino-2-sulfamoyl-phenyl)-malonamicacid ethyl ester can be prepared as follows:

To 2-amino-5-methanesulfonylamino-benzenesulfonamide (Example 17d, 175mg, 0.66 mmol) was added diethyl malonate (297 mg, 1.66 mmol) and heatedat 160° C. for 60 min. After cooling down to 25° C., a 1:1 mixture ofethyl acetate/hexanes (5 mL) was added, upon which as a white solidprecipitated out. The solid was collected by vacuum filtration, washedtwice with a 1:1 mixture of ethyl acetate/hexanes, and dried under highvacuum to afford the desired product,N-(4-methanesulfonylamino-2-sulfamoyl-phenyl)-malonamic acid ethyl ester(179 mg, 0.47 mmol, 72% yield) as an off-white solid. ¹H NMR (400 MHz,CD₃OD) δ: 1.32 (t, 3H, J=7.0 Hz), 3.00 (s, 3H), 3.60 (s, 2H), 4.25(quartet, 2H, J=6.8 Hz), 7.44 (dd, 1H, J₁=3.2 Hz, J₂=8.4 Hz), 7.87 (d,1H, J=5.6 Hz), 7.92 (d, 1H, J=8.4 Hz). LC-MS (ESI⁺) calcd forC₁₂H₁₇N₃O₇S₂ 379.05. found 380.1 [M+H⁺].

f) N-(4-Methanesulfonylamino-2-sulfamoylphenyl)malonamic acid methylester

Methyl malonyl chloride (9.05 mL, 84.4 mmol) was added dropwise over 10min to a solution of 2-amino-5-methanesulfonylaminobenzenesulfonamide(Example 17d, 20.35 g, 76.7 mmol) in N,N-dimethylacetamide (90 mL) at 0°C. The mixture was allowed to warm to 25° C. and stirred at thattemperature for 1 h. A solution of sodium bicarbonate (7.09 g, 84.4mmol) in water (200 mL) was then added via addition funnel over 15 min(gas evolution and a mild exotherm were noted) followed by the rapidaddition of an additional volume of water (200 mL). The resultingsolution was then seeded with a small amount ofN-(4-methanesulfonylamino-2-sulfamoylphenyl)malonamic acid methyl ester(ca. 15 mg). The mixture was stirred for 21 h at 25° C. during whichtime a tan precipitate formed. This material was collected byfiltration, washed with water (150 mL), and was dried in a vacuum ovenat 50° C. to afford the desired product,N-(4-methanesulfonylamino-2-sulfamoylphenyl)-malonamic acid methyl ester(24.33 g, 66.6 mmol, 87% yield) as a tan solid. ¹H NMR (400 MHz,DMSO-d₆) δ: 3.02 (3H, s), 3.60 (2H, s), 3.66 (3H, s), 7.38 (1H, dd,J₁=2.3 Hz, J₂=8.6 Hz), 7.53 (2H, bs), 7.73 (1H, d, J=2.4 Hz), 7.83 (1H,d, J=8.7 Hz), 9.43 (1H, s), 9.99 (1H, s).

g)(7-Methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid

N-(4-Methanesulfonylamino-2-sulfamoyl-phenyl)-malonamic acid ethyl ester(Example 17e, 9.55 g, 26.16 mmol) was dissolved in 8% aqueous sodiumhydroxide solution (262 mL) and heated at 100° C. for 1.5 h. Thereaction mixture was cooled to 0° C. and the solution was acidified byslowly adding 12.0 M aqueous hydrochloric acid solution until pH 1-2 wasreached. A precipitate started to form and the suspension was allowed tostir for 30 min at 0° C. The precipitate was collected by vacuumfiltration, washed with cold water, and dried under high vacuum toafford(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid (7.20 g, 21.621 mmol, 82.6% yield) as a pinkish solid. ¹H NMR (400MHz, DMSO-d₆) δ: 3.03 (3H, s), 3.56 (2H, s), 7.33 (1H, d, J=9.1 Hz),7.52-7.54 (2H, m), 10.09 (1H, s), 12.24 (1H, s), 13.02 (1H, bs). LC-MS(ESI) calcd for C₁₀H₁₁N₃O₆S₂ 333.01. found 334.1 [M+H⁺].

Alternatively,(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid can be prepared from 17f as follows:N-(4-Methanesulfonylamino-2-sulfamoylphenyl)-malonamic acid methyl ester(Example 17f, 21.75 g, 59.53 mmol) was dissolved in an aqueous solutionof sodium hydroxide (7.14 g, 178.5 mmol; dissolved in 180 mL water) at25° C. The reaction mixture was heated to 100° C. for 1 h, then wasgradually cooled over 30 min to 0° C. 12.0 M Aqueous hydrochloric acidsolution (20 mL, 240 mmol) was added dropwise over 10 min via additionfunnel resulting in the formation of a tan precipitate. The mixture wasallowed to warm to 25° C. and was stirred at that temperature for 21 h.The precipitate was collected by filtration, washed with water (150 mL),and was dried in a vacuum oven at 45° C. for 22 h to afford(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid (18.36 g, 55.1 mmol, 93% yield) as a tan solid. ¹H NMR (400 MHz,DMSO-d₆) δ: 3.03 (3H, s), 3.56 (2H, s), 7.32-7.34 (1H, m), 7.51-7.54(2H, m), 10.09 (1H, s), 12.26 (1H, s), 13.01 (1H, bs). LC-MS (ESI) calcdfor C₁₀H₁₁N₃O₆S₂ 333.01. found 334.1 [M+H⁺].

h) 1-(3-Chloro-4-fluoro-benzylamino)-1H-pyrrole-2-carboxylic acid allylester

Sodium cyanoborohydride (1.11 g, 16.8 mmol) was added to a solution of1-amino-1H-pyrrole-2-carboxylic acid allyl ester (Example 1b, 1.12 g,6.74 mmol), 3-chloro-4-fluorobenzaldehyde (1.32 g, 8.08 mmol) and aceticacid (1.2 mL), in methanol (50 mL) at 25° C. The reaction mixture wasstirred at 25° C. for 18 h, quenched with saturated aqueous sodiumbicarbonate solution and was extracted with ethyl acetate (2×50 mL). Theorganic layers were dried over magnesium sulfate, filtered andconcentrated in vacuo. Purification of the residue by flash columnchromatography (Teledyne Isco RediSep 40 g, 0→40% ethyl acetate inhexanes) afforded the desired product,1-(3-chloro-4-fluoro-benzylamino)-1H-pyrrole-2-carboxylic acid allylester (1.36 g, 4.41 mmol, 65% yield) as an off-white oil. ¹H NMR (400MHz, CDCl₃) δ 4.06 (2H, d, J=5.5 Hz), 4.76 (2H, d, J=5.3 Hz), 5.29 (1H,d, J=11.0 Hz), 5.40 (1H, d, J=16.4 Hz), 5.96-6.05 (2H, m), 6.58 (1H, t,J=5.5 Hz), 6.76 1H, (t, J=1.9 Hz), 6.91 (1H, dd, J₁=4.3 Hz, J₂=1.8 Hz),7.06 (1H, t, J=8.6 Hz), 7.10-7.14 (1H, m), 7.33 (1H, dd, J₁=7.1 Hz,J₂=1.4 Hz).

i)1-{(3-Chloro-4-fluoro-benzyl)-[2-(7-methanesulfonylmethyl-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-acetyl]-amino}-1H-pyrrole-2-carboxylicacid allyl ester

To a solution of1-(3-chloro-4-fluoro-benzylamino)-1H-pyrrole-2-carboxylic acid allylester (Example 17h, 150.7 mg, 0.488 mmol) in N,N-dimethylformamide (3.0mL) was added(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-aceticacid (Example 17f, 195.2 mg, 0.586 mmol), 4-dimethylaminopyridine (18.1mg, 0.147 mmol), and 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimidehydrochloride (1114.5 mg, 0.586 mmol). After stirring at 25° C. for 12h, the mixture was diluted with ethyl acetate and acidified with 1.0 Maqueous hydrochloric acid solution to pH 1. The organic layer wasseparated and the aqueous layer was extracted with ethyl acetate (2×20mL). The combined organic layers were dried over anhydrous magnesiumsulfate, filtered, concentrated and dried in vacuo to afford the crudedesired product,1-{(3-chloro-4-fluoro-benzyl)-[2-(7-methanesulfonylmethyl-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-acetyl]-amino}-1H-pyrrole-2-carboxylicacid allyl ester as a faintly yellow oil. The crude desired product wasused in the next step without further purification. LC-MS (ESI) calcdfor C₂₅H₂₃ClFN₅O₇S₂ 623.07. found 624.2 [M+H⁺].

j)N-{3-[1-(3-Chloro-4-fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide

To a solution of1-{(3-chloro-4-fluoro-benzyl)-[2-(7-methanesulfonylmethyl-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-3-yl)-acetyl]-amino}-1H-pyrrole-2-carboxylicacid allyl ester (Example 171, 304.5 mg, 0.488 mmol) in absolute ethanol(5 mL) was added a 21% solution of sodium ethoxide in ethanol (1.1 mL,2.95 mmol). After stirring at 60° C. for 12 h, the mixture was dilutedwith ethyl acetate and acidified with 1.0 M aqueous hydrochloric acidsolution upon which a precipitate formed. The solid was collected byvacuum filtration to afford the desired product,N-{3-[1-(3-chloro-4-fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide(88.5 mg, 0.156 mmol, 32% yield) as an off-white solid. The filtrate wasextracted with ethyl acetate (2×20 mL). The combined organic layers weredried over anhydrous magnesium sulfate, filtered and concentrated invacuo. The crude mixture was purified by HPLC purification (Column Luna5μ C18 (2) 100 Å AXIA 150×21.2 mm, 5 micron, 25%-100% in 12 min 30mL/min flow rate, 0.05% trifluoroacetic acid in acetonitrile/0.05%trifluoroacetic acid in water) to afford more of the desired product,N-{3-[1-(3-chloro-4-fluoro-benzyl)-4-hydroxy-2-oxo-1,2-dihydro-pyrrolo[1,2-b]pyridazin-3-yl]-1,1-dioxo-1,4-dihydro-1λ⁶-benzo[1,2,4]thiadiazin-7-yl}-methanesulfonamide(18.4 mg, 0.033 mmol, 7% yield; total 39% yield) as an off-white solid.¹H NMR (400 MHz, DMSO-d₆) δ 3.06 (3H, s), 5.61 (2H, s), 6.57 (1H, s)6.98 (1H, s), 7.37 (2H, d, J=7.6 Hz), 7.52 (1H, dd, J₁=8.5 Hz, J₂=2.4Hz), 7.59-7.68 (4H, m), 10.17 (1H, s). LC-MS (ESI) calcd forC₂₂H₁₇ClFN₅O₆S₂ 565.03. found 566.2 [M+H⁺].

Biological Testing

The ability of compounds of Formula I to inhibit HCV replication can bedemonstrated in the following in vitro assays.

Compounds were tested for HCV polymerase inhibition. Assays wereperformed in a 96-well streptavidin-coated FlashPlate using 20 nMenzyme, 0.5 μCi of [α-³³P]GTP, 0.6 μM GTP, and 250 nM 5′biotinylatedoligo (rG₁₃)/poly rC in 20 mM Tris-HCl, pH 7.5, 5 mM MgCl₂, 5 mMdithiothreitol, 0.1 g/L bovine serum albumin, and 100 U/mL RNAseinhibitor. The reaction was stopped by aspiration after 75 min at 28° C.and the plate was washed several times. After washing and drying theplate, incorporated radioactivity was counted using a Microbetascintillation counter. IC₅₀ values were calculated relative to theuninhibited control and inhibition data were fitted to a 4-parameterIC₅₀ equation. For very potent inhibitors, the data were fitted to atight binding quadratic equation to obtain IC₅₀ values.

Test results (IC₅₀ values) for compounds of Formula I are summarized inTable 1, wherein ++ means NS5B polymerase inhibition with IC₅₀ valuesless than 0.10 μM, and + means IC₅₀ values between 0.10 μM and 3 μM.TABLE 1 NS5B Polymerase Example # IC50 1 + 2 + 3 ++ 4 ++ 5 ++ 6 + 7 + 8++ 9 ++ 10 + 11 + 12 + 13 + 14 ++ 15 + 16 ++ 17 ++HCV Replicon Assay (Replicon EC₅₀ (μM))

The cell culture component of the assay is performed essentially asdescribed by Bartenschlager et al., Hepatology, 35, 694-703 (2002),wherein exponentially growing HCV Huh-7/C24 replicon cells are seeded at4.5×10³ cells/well in 96 well plates and 24 hours later are treated withsix point half-log concentration of compound. After 72 hours exposurethe media is discarded from the compound assay plate and the cellmonolayers are lysed by addition of 150 μl lysis mixture (Genospectra)with incubation at 53° C. for 45 minutes. Following incubation, eachlysate is thoroughly mixed and 5 μl (NS3 probe) or 10 μl (GAPDH probe)of each lysate is then transferred to the capture plate and analyzed bybDNA assay.

Branched DNA (bDNA) Assay

Based on provided sequences for NS3 [AJ242652], Genospectra (Fremont,Calif., USA) designed and synthesized probes to these analytes (togetherwith GAPDH). Cellular bDNA analysis is carried out essentially asdescribed in the Genospectra protocol (details in Shyamala, V. et al.,Anal Biochem, 266, 140-7 (1999)), wherein target specific captureextenders, label extenders and blocking probes are added to the captureplate after the addition of 5 or 10 μl cell lysate. After annealingovernight, during which the target RNA is captured to the plate viainteraction with the capture extenders, the plate is washed, and thenamplifier (which binds via the label extenders) and label probe aresequentially added.

After subsequent addition of the chemilumigenic substrate (dioxetan),each plate is read by luminometer (Wallac 1420 Multilabel HTS CounterVictor 2). The luminescence signal is proportional to the amount of mRNApresent in each lysate. In addition to the samples, cell lysate only (noprobe) background controls are also included on each bDNA assay plateand the average signal from these control wells is subtracted from thesample reading prior to analysis. Percent of no drug control isdetermined for both the NS3 and GAPDH signals for each compound also.Percent inhibition is determined for each compound concentration inrelation to the no drug control to calculate the EC₅₀.

It is to be understood that the foregoing description is exemplary andexplanatory in nature, and is intended to illustrate the invention andits preferred embodiments. Through routine experimentation, the artisanwill recognize apparent modifications and variations that may be madewithout departing from the spirit of the invention.

1. A compound according to Formula I:

wherein R¹ is independently 1-3 moieties selected from hydrogen, halo,cyano, nitro, hydroxy, —NR⁸R⁹, C₃-C₈ cycloalkyl, C₁-C₆ alkyl, alkenyl,alkynyl, C₁-C₆ haloalkyl, C₁-C₆ hydroxyalkyl, C₁-C₆ alkoxy, —(C₁-C₆alkylene)NR⁸R⁹, —C(O)OH, —C(O)O(C₁-C₆ alkyl), —C(O)NH(C₁-C₆ alkyl),—C(O)(C₁-C₆ alkyl), aryl, or heterocyclyl having 1, 2, or 3 N, O, or Satoms, wherein R⁸ and R⁹ are independently H, C₁-C₆ alkyl, C₃-C₈cycloalkyl, aryl, or heterocyclyl, or R⁸ and R⁹ combine with the N atomto which they are attached to form a 5- or 6-membered heterocyclyl ring,R² is hydrogen, C₃-C₈ cycloalkyl, C₁-C₇ alkyl, alkenyl, alkynyl, C₁-C₆haloalkyl, C₁-C₆ hydroxyalkyl, C₁-C₆ alkoxy, aryl, or heterocyclylhaving 1, 2, or 3 N, O, or S atoms, R³ is hydrogen or C₁-C₆ alkyl, R⁴ isselected from

wherein n is 0, 1, or 2, R⁵ is hydrogen or C₁-C₆ alkyl, R⁶ is hydrogen,halo, or C₁-C₆ alkyl, and Ring A is 5 or 6-membered aryl orheterocyclyl, optionally substituted by 1-3 R⁷ moieties, wherein R⁷ isH, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, halo, cyano, nitro, OH,—O-alkyl, —O—(C₁-C₆ hydroxyalkyl), —O—(C₁-C₆ alkoxy), —O—(C₁-C₆alkylene)-cyano, —O—(C₁-C₆ alkylene)-C(O)R¹⁰, —OCHR¹⁰C(O)O—R¹¹,—OCHR¹⁰C(O)NHOH, —O—(C₁-C₆ alkyl)-C(O)NR¹¹R¹², —O—(C₁-C₆alkylene)-NR¹⁰C(O)R¹¹, —O—(C₁-C₆ alkylene)-NR¹⁰C(O)OR¹¹, —O—(C₁-C₆alkylene)-NR¹⁰C(O)NR¹¹R¹², —OCHR¹⁰C(O)NR¹¹R¹², —O—(C₁-C₆alkylene)-S(O)R¹⁰, —O—(C₁-C₆ alkyl)-S(O)₂R¹⁰, —O—(C₁-C₆alkylene)-S(O)₂NR¹¹R¹², —O—(C₁-C₆ alkylene)-NR¹⁰S(O)₂NR¹¹R¹², —O—(C₁-C₆alkylene)-NR¹⁰S(O)₂R¹¹, —O—(C₁-C₆ alkylene)-S(O)₂R¹⁰, —O—(C₁-C₆alkylene)-NR¹¹R¹², —(C₁-C₆ alkylene)-S(O)₂R¹⁰, —(C₁-C₆alkylene)-S(O)₂NR¹¹R¹², —(C₁-C₆ alkylene)-S(O)R¹⁰, —(C₁-C₆alkylene)-C(O)R¹⁰, —(C₁-C₆ alkylene)-C(O)NR¹¹R¹², —(C₁-C₆alkylene)-NR¹⁰C(O)R¹¹, —(C₁-C₆ alkylene)-NR¹⁰S(O)₂R¹¹, —(C₁-C₆alkylene)-NR¹⁰C(O)OR¹¹, —(C₁-C₆ alkylene)-NR¹⁰C(O)NR¹¹R¹², —(C₁-C₆alkylene)-NR¹⁰S(O)₂NR¹¹R¹², —(C₁-C₆ alkylene)-C(O)OR¹⁰, —(C₁-C₆alkylene)-NR¹¹R¹², —NR¹¹R¹², —NR¹¹C(O)R¹², —NR¹⁰S(O)₂R¹¹,—NR¹⁰S(O)₂NR¹¹R¹², —C(O)R¹⁰, —S(O)R¹⁰, —S(O)₂R¹⁰, or —S(O)₂NR¹¹R¹²,wherein R¹⁰, R¹¹, and R¹² are independently H, C₁-C₆ alkyl, C₃-C₈cycloalkyl, aryl, or heterocyclyl, or R¹⁰ and R¹¹ or R¹¹ and R¹² combinewith the atom(s) to which they are attached to form a 5- or 6-memberedheterocyclyl ring, wherein the above alkyl, alkenyl, alkynyl, aryl,cycloalkyl, or heterocyclyl moieties provided in R¹, R², R⁷, R⁸, R⁹,R¹⁰, R¹¹, and R¹² are each optionally and independently substituted by1-3 substituents selected from alkylamine, amino, aryl, cycloalkyl,heterocyclyl, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ hydroxyalkyl, C₁-C₆alkoxy, C₁-C₆ alkylamine, C₁-C₆ dialkylamine, C₂-C₆ alkenyl, or C₂-C₆alkynyl, wherein each of which may be interrupted by one or more heteroatoms, carboxyl, cyano, halo, hydroxy, nitro, oxo, —C(O)OH,—C(O)₂—(C₁-C₆ alkyl), —C(O)₂—(C₃-C₈ cycloalkyl), —C(O)₂-(aryl),—C(O)₂-(heterocyclyl), —C(O)₂—(C₁-C₆ alkylene)aryl, —C(O)₂—(C₁-C₆alkylene)heterocyclyl, —C(O)₂—(C₁-C₆ alkylene)cycloalkyl, —C(O)(C₁-C₆alkyl), —C(O)(C₃-C₈ cycloalkyl), —C(O)(aryl), —C(O)(heterocyclyl),—C(O)(C₁-C₆ alkylene)aryl, —C(O)(C₁-C₆ alkylene)heterocyclyl, and—C(O)(C₁-C₆ alkyl)cycloalkyl, wherein each of the above optionalsubstituents can be further optionally substituted by 1-5 substituentsselected from amino, cyano, halo, hydroxy, nitro, C₁-C₆ alkylamine,C₁-C₆ dialkylamine, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, and C₁-C₆hydroxyalkyl, wherein each alkyl is optionally substituted by one ormore halo substituents, or a pharmaceutically acceptable salt, hydrate,tautomer or stereoisomer thereof.
 2. The compound of claim 1 wherein R¹is selected from hydrogen, halo, cyano, hydroxyl, —NR⁸R⁹, C₃-C₈cycloalkyl, C₁-C₆ alkyl, alkenyl, alkynyl, C₁-C₆ alkoxy, —(C₁-C₆alkylene)NR⁸R⁹, —C(O)OR⁸, —C(O)NR⁸R⁹, —C(O)R⁸, aryl, or heterocyclylhaving 1, 2, or 3 N, O, or S atoms, wherein R⁸ and R⁹ are independentlyH, C₁-C₆ alkyl, C₃-C₈ cycloalkyl, aryl, or heterocyclyl, or R⁸ and R⁹combine with the N atom to which they are attached to form a 5- or6-membered heterocyclyl ring.
 3. The compound of claim 1 wherein R¹ isselected from

wherein R¹³, R¹⁴ and R¹⁵ are independently selected from hydrogen,alkylamine, amino, aryl, cycloalkyl, heterocyclyl, C₁-C₆ alkyl, C₁-C₆alkoxy, carboxyl, cyano, halo, and hydroxyl, or R¹³ and R¹⁴ combine withthe N atom to which they are attached to form a 5- or 6-memberedheterocyclyl ring.
 4. The compound of claim 1 wherein R¹ is selectedfrom hydrogen, fluoro, cyano, and methyl.
 5. The compound of claim 1wherein R² is selected from C₃-C₈ cycloalkyl, C₁-C₆ alkyl, alkenyl,alkynyl, aryl, and heterocyclyl having 1, 2, or 3 N, O, or S atoms,wherein the alkyl, alkenyl, alkynyl, aryl, cycloalkyl, or heterocyclylmoieties are each optionally and independently substituted by 1-3substituents selected from aryl, cycloalkyl, heterocyclyl, C₁-C₆ alkyl,C₁-C₆ alkoxy, C₁-C₆ alkylamine, C₂-C₆ alkenyl, or C₂-C₆ alkynyl, whereineach of which may be interrupted by one or more hetero atoms andoptionally substituted by cyano or halo.
 6. The compound of claim 1wherein R² is selected from

wherein X is O or S and n=0, 1, or
 2. 7. The compound of claim 6 whereinR² is selected from


8. The compound of claim 6 wherein R² is selected from


9. The compound of claim 1 wherein R³ and R⁵ are independently selectedfrom hydrogen, methyl, and ethyl.
 10. The compound of claim 1 wherein R⁶is selected from hydrogen, fluoro, methyl, and ethyl.
 11. The compoundof claim 1 wherein n is
 2. 12. The compound of claim 1 wherein Ring A isselected from

wherein X is S, O, NH, or —N(C₁-C₆ alkyl).
 13. The compound of claim 12wherein Ring A is selected from


14. The compound of claim 13 wherein Ring A is

wherein R⁷ is hydrogen, —(C₁-C₆ alkylene)-S(O)₂NR¹¹R¹², —(C₁-C₆alkylene)-S(O)R¹⁰, —(C₁-C₆ alkylene)-S(O)₂R¹⁰, —NR¹⁰S(O)₂R¹¹, or—NR¹⁰S(O)₂NR¹¹R¹².
 15. The compound of claim 1 wherein R⁷ is selectedfrom

wherein n is an integer from 0 to 6, m is an integer from 1 to 6, R¹⁶,R¹⁷, and R¹⁸ are independently selected from hydrogen, C₁-C₆ alkyl,C₃-C₈ cycloalkyl, aryl, and heterocyclyl, or R¹⁶ and R¹⁷ or R¹⁷ and R¹⁸combine with the atom(s) to which they are attached to form a 5- or6-membered heterocyclyl ring, R¹⁹ is hydrogen, C₁-C₆ alkyl, C₃-C₈cycloalkyl —S(O)₂R¹⁰, or —S(O)₂NR¹¹R¹², wherein R¹⁰, R¹¹, and R¹² areindependently selected from hydrogen, C₁-C₆ alkyl, C₃-C₈ cycloalkyl,aryl, or heterocyclyl, or R¹¹ and R¹² combine with the N atom to whichthey are attached to form a 5- or 6-membered heterocyclyl ring.
 16. Thecompound of claim 1 selected from


17. A compound selected from


18. A pharmaceutically acceptable composition comprising a compound ofclaim 1 and a pharmaceutically acceptable carrier.
 19. A method ofinhibiting hepatitis C virus replication comprising exposing hepatitis Cvirus to a therapeutically effective concentration of a compound ofclaim
 1. 20. A method of treating a cell having at least some elementsof hepatitis C virus comprising incubating said cell with a compound ofclaim
 1. 21. A method for treating or preventing hepatitis C virusinfection in a mammal in need thereof, comprising administering to themammal a therapeutically or prophylactically effective amount of acompound of claim
 1. 22. The method of claim 21 wherein the mammal is ahuman.
 23. The method of claim 21 further comprising administering anadditional therapeutic agent to the mammal.
 24. The method of claim 23wherein the additional therapeutic agent is selected from the groupconsisting of an antibiotic, an antiemetic agent, an antidepressant, anantifungal agent, an anti-inflammatory agent, an antiviral agent, ananticancer agent, an immunomodulatory agent, an α-interferon, aβ-interferon, a ribavirin, an alkylating agent, a hormone, a cytokineand a toll receptor-like modulator.
 25. The method of claim 23 whereinthe additional therapeutic agent is a toll receptor-like modulator.